_ Git - ldk-c-bindings/blob - c-bindings-gen/src/types.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE>
   5 // or the MIT license <LICENSE-MIT>, at your option.
   6 // You may not use this file except in accordance with one or both of these
   7 // licenses.
   8
   9 use std::cell::RefCell;
  10 use std::collections::{HashMap, HashSet};
  11 use std::fs::File;
  12 use std::io::Write;
  13 use std::hash;
  14
  15 use crate::blocks::*;
  16
  17 use proc_macro2::{TokenTree, Span};
  18 use quote::format_ident;
  19 use syn::parse_quote;
  20
  21 // The following utils are used purely to build our known types maps - they break down all the
  22 // types we need to resolve to include the given object, and no more.
  23
  24 pub fn first_seg_self<'a>(t: &'a syn::Type) -> Option<impl Iterator<Item=&syn::PathSegment> + 'a> {
  25         match t {
  26                 syn::Type::Path(p) => {
  27                         if p.qself.is_some() || p.path.leading_colon.is_some() {
  28                                 return None;
  29                         }
  30                         let mut segs = p.path.segments.iter();
  31                         let ty = segs.next().unwrap();
  32                         if !ty.arguments.is_empty() { return None; }
  33                         if format!("{}", ty.ident) == "Self" {
  34                                 Some(segs)
  35                         } else { None }
  36                 },
  37                 _ => None,
  38         }
  39 }
  40
  41 pub fn get_single_remaining_path_seg<'a, I: Iterator<Item=&'a syn::PathSegment>>(segs: &mut I) -> Option<&'a syn::Ident> {
  42         if let Some(ty) = segs.next() {
  43                 if !ty.arguments.is_empty() { unimplemented!(); }
  44                 if segs.next().is_some() { return None; }
  45                 Some(&ty.ident)
  46         } else { None }
  47 }
  48
  49 pub fn first_seg_is_stdlib(first_seg_str: &str) -> bool {
  50         first_seg_str == "std" || first_seg_str == "core" || first_seg_str == "alloc"
  51 }
  52
  53 pub fn single_ident_generic_path_to_ident(p: &syn::Path) -> Option<&syn::Ident> {
  54         if p.segments.len() == 1 {
  55                 Some(&p.segments.iter().next().unwrap().ident)
  56         } else { None }
  57 }
  58
  59 pub fn path_matches_nongeneric(p: &syn::Path, exp: &[&str]) -> bool {
  60         if p.segments.len() != exp.len() { return false; }
  61         for (seg, e) in p.segments.iter().zip(exp.iter()) {
  62                 if seg.arguments != syn::PathArguments::None { return false; }
  63                 if &format!("{}", seg.ident) != *e { return false; }
  64         }
  65         true
  66 }
  67
  68 pub fn string_path_to_syn_path(path: &str) -> syn::Path {
  69         let mut segments = syn::punctuated::Punctuated::new();
  70         for seg in path.split("::") {
  71                 segments.push(syn::PathSegment {
  72                         ident: syn::Ident::new(seg, Span::call_site()),
  73                         arguments: syn::PathArguments::None,
  74                 });
  75         }
  76         syn::Path { leading_colon: Some(syn::Token![::](Span::call_site())), segments }
  77 }
  78
  79 #[derive(Debug, PartialEq)]
  80 pub enum ExportStatus {
  81         Export,
  82         NoExport,
  83         TestOnly,
  84         /// This is used only for traits to indicate that users should not be able to implement their
  85         /// own version of a trait, but we should export Rust implementations of the trait (and the
  86         /// trait itself).
  87         /// Concretly, this means that we do not implement the Rust trait for the C trait struct.
  88         NotImplementable,
  89 }
  90 /// Gets the ExportStatus of an object (struct, fn, etc) given its attributes.
  91 pub fn export_status(attrs: &[syn::Attribute]) -> ExportStatus {
  92         for attr in attrs.iter() {
  93                 let tokens_clone = attr.tokens.clone();
  94                 let mut token_iter = tokens_clone.into_iter();
  95                 if let Some(token) = token_iter.next() {
  96                         match token {
  97                                 TokenTree::Punct(c) if c.as_char() == '=' => {
  98                                         // Really not sure where syn gets '=' from here -
  99                                         // it somehow represents '///' or '//!'
 100                                 },
 101                                 TokenTree::Group(g) => {
 102                                         if format!("{}", single_ident_generic_path_to_ident(&attr.path).unwrap()) == "cfg" {
 103                                                 let mut iter = g.stream().into_iter();
 104                                                 if let TokenTree::Ident(i) = iter.next().unwrap() {
 105                                                         if i == "any" {
 106                                                                 // #[cfg(any(test, feature = ""))]
 107                                                                 if let TokenTree::Group(g) = iter.next().unwrap() {
 108                                                                         let mut all_test = true;
 109                                                                         for token in g.stream().into_iter() {
 110                                                                                 if let TokenTree::Ident(i) = token {
 111                                                                                         match format!("{}", i).as_str() {
 112                                                                                                 "test" => {},
 113                                                                                                 "feature" => {},
 114                                                                                                 _ => all_test = false,
 115                                                                                         }
 116                                                                                 } else if let TokenTree::Literal(lit) = token {
 117                                                                                         if format!("{}", lit) != "fuzztarget" {
 118                                                                                                 all_test = false;
 119                                                                                         }
 120                                                                                 }
 121                                                                         }
 122                                                                         if all_test { return ExportStatus::TestOnly; }
 123                                                                 }
 124                                                         } else if i == "test" {
 125                                                                 return ExportStatus::TestOnly;
 126                                                         }
 127                                                 }
 128                                         }
 129                                         continue; // eg #[derive()]
 130                                 },
 131                                 _ => unimplemented!(),
 132                         }
 133                 } else { continue; }
 134                 match token_iter.next().unwrap() {
 135                         TokenTree::Literal(lit) => {
 136                                 let line = format!("{}", lit);
 137                                 if line.contains("(C-not exported)") || line.contains("This is not exported to bindings users") {
 138                                         return ExportStatus::NoExport;
 139                                 } else if line.contains("(C-not implementable)") {
 140                                         return ExportStatus::NotImplementable;
 141                                 }
 142                         },
 143                         _ => unimplemented!(),
 144                 }
 145         }
 146         ExportStatus::Export
 147 }
 148
 149 pub fn assert_simple_bound(bound: &syn::TraitBound) {
 150         if bound.paren_token.is_some() { unimplemented!(); }
 151         if let syn::TraitBoundModifier::Maybe(_) = bound.modifier { unimplemented!(); }
 152 }
 153
 154 /// Returns true if the enum will be mapped as an opaue (ie struct with a pointer to the underlying
 155 /// type), otherwise it is mapped into a transparent, C-compatible version of itself.
 156 pub fn is_enum_opaque(e: &syn::ItemEnum) -> bool {
 157         for var in e.variants.iter() {
 158                 if let syn::Fields::Named(fields) = &var.fields {
 159                         for field in fields.named.iter() {
 160                                 match export_status(&field.attrs) {
 161                                         ExportStatus::Export|ExportStatus::TestOnly => {},
 162                                         ExportStatus::NotImplementable => panic!("(C-not implementable) should only appear on traits!"),
 163                                         ExportStatus::NoExport => return true,
 164                                 }
 165                         }
 166                 } else if let syn::Fields::Unnamed(fields) = &var.fields {
 167                         for field in fields.unnamed.iter() {
 168                                 match export_status(&field.attrs) {
 169                                         ExportStatus::Export|ExportStatus::TestOnly => {},
 170                                         ExportStatus::NotImplementable => panic!("(C-not implementable) should only appear on traits!"),
 171                                         ExportStatus::NoExport => return true,
 172                                 }
 173                         }
 174                 }
 175         }
 176         false
 177 }
 178
 179 /// A stack of sets of generic resolutions.
 180 ///
 181 /// This tracks the template parameters for a function, struct, or trait, allowing resolution into
 182 /// a concrete type. By pushing a new context onto the stack, this can track a function's template
 183 /// parameters inside of a generic struct or trait.
 184 ///
 185 /// It maps both direct types as well as Deref<Target = X>, mapping them via the provided
 186 /// TypeResolver's resolve_path function (ie traits map to the concrete jump table, structs to the
 187 /// concrete C container struct, etc).
 188 #[must_use]
 189 pub struct GenericTypes<'a, 'b> {
 190         self_ty: Option<String>,
 191         parent: Option<&'b GenericTypes<'b, 'b>>,
 192         typed_generics: HashMap<&'a syn::Ident, String>,
 193         default_generics: HashMap<&'a syn::Ident, (syn::Type, syn::Type, syn::Type)>,
 194 }
 195 impl<'a, 'p: 'a> GenericTypes<'a, 'p> {
 196         pub fn new(self_ty: Option<String>) -> Self {
 197                 Self { self_ty, parent: None, typed_generics: HashMap::new(), default_generics: HashMap::new(), }
 198         }
 199
 200         /// push a new context onto the stack, allowing for a new set of generics to be learned which
 201         /// will override any lower contexts, but which will still fall back to resoltion via lower
 202         /// contexts.
 203         pub fn push_ctx<'c>(&'c self) -> GenericTypes<'a, 'c> {
 204                 GenericTypes { self_ty: None, parent: Some(self), typed_generics: HashMap::new(), default_generics: HashMap::new(), }
 205         }
 206
 207         /// Learn the generics in generics in the current context, given a TypeResolver.
 208         pub fn learn_generics_with_impls<'b, 'c>(&mut self, generics: &'a syn::Generics, impld_generics: &'a syn::PathArguments, types: &'b TypeResolver<'a, 'c>) -> bool {
 209                 let mut new_typed_generics = HashMap::new();
 210                 // First learn simple generics...
 211                 for (idx, generic) in generics.params.iter().enumerate() {
 212                         match generic {
 213                                 syn::GenericParam::Type(type_param) => {
 214                                         let mut non_lifetimes_processed = false;
 215                                         'bound_loop: for bound in type_param.bounds.iter() {
 216                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
 217                                                         if let Some(ident) = single_ident_generic_path_to_ident(&trait_bound.path) {
 218                                                                 match &format!("{}", ident) as &str { "Send" => continue, "Sync" => continue, "Sized" => continue, _ => {} }
 219                                                         }
 220                                                         if path_matches_nongeneric(&trait_bound.path, &["core", "clone", "Clone"]) { continue; }
 221
 222                                                         assert_simple_bound(&trait_bound);
 223                                                         if let Some(path) = types.maybe_resolve_path(&trait_bound.path, None) {
 224                                                                 if types.skip_path(&path) { continue; }
 225                                                                 if path == "Sized" { continue; }
 226                                                                 if non_lifetimes_processed { return false; }
 227                                                                 non_lifetimes_processed = true;
 228                                                                 if path != "std::ops::Deref" && path != "core::ops::Deref" &&
 229                                                                         path != "std::ops::DerefMut" && path != "core::ops::DerefMut"  {
 230                                                                         let p = string_path_to_syn_path(&path);
 231                                                                         let ref_ty = parse_quote!(&#p);
 232                                                                         let mut_ref_ty = parse_quote!(&mut #p);
 233                                                                         self.default_generics.insert(&type_param.ident, (syn::Type::Path(syn::TypePath { qself: None, path: p }), ref_ty, mut_ref_ty));
 234                                                                         new_typed_generics.insert(&type_param.ident, Some(path));
 235                                                                 } else {
 236                                                                         // If we're templated on Deref<Target = ConcreteThing>, store
 237                                                                         // the reference type in `default_generics` which handles full
 238                                                                         // types and not just paths.
 239                                                                         if let syn::PathArguments::AngleBracketed(ref args) =
 240                                                                                         trait_bound.path.segments[0].arguments {
 241                                                                                 assert_eq!(trait_bound.path.segments.len(), 1);
 242                                                                                 for subargument in args.args.iter() {
 243                                                                                         match subargument {
 244                                                                                                 syn::GenericArgument::Lifetime(_) => {},
 245                                                                                                 syn::GenericArgument::Binding(ref b) => {
 246                                                                                                         if &format!("{}", b.ident) != "Target" { return false; }
 247                                                                                                         let default = &b.ty;
 248                                                                                                         self.default_generics.insert(&type_param.ident, (parse_quote!(&#default), parse_quote!(&#default), parse_quote!(&mut #default)));
 249                                                                                                         break 'bound_loop;
 250                                                                                                 },
 251                                                                                                 _ => unimplemented!(),
 252                                                                                         }
 253                                                                                 }
 254                                                                         } else {
 255                                                                                 new_typed_generics.insert(&type_param.ident, None);
 256                                                                         }
 257                                                                 }
 258                                                         }
 259                                                 }
 260                                         }
 261                                         if let Some(default) = type_param.default.as_ref() {
 262                                                 assert!(type_param.bounds.is_empty());
 263                                                 self.default_generics.insert(&type_param.ident, (default.clone(), parse_quote!(&#default), parse_quote!(&mut #default)));
 264                                         } else if type_param.bounds.is_empty() {
 265                                                 if let syn::PathArguments::AngleBracketed(args) = impld_generics {
 266                                                         match &args.args[idx] {
 267                                                                 syn::GenericArgument::Type(ty) => {
 268                                                                         self.default_generics.insert(&type_param.ident, (ty.clone(), parse_quote!(&#ty), parse_quote!(&mut #ty)));
 269                                                                 }
 270                                                                 _ => unimplemented!(),
 271                                                         }
 272                                                 }
 273                                         }
 274                                 },
 275                                 _ => {},
 276                         }
 277                 }
 278                 // Then find generics where we are required to pass a Deref<Target=X> and pretend its just X.
 279                 if let Some(wh) = &generics.where_clause {
 280                         for pred in wh.predicates.iter() {
 281                                 if let syn::WherePredicate::Type(t) = pred {
 282                                         if let syn::Type::Path(p) = &t.bounded_ty {
 283                                                 if first_seg_self(&t.bounded_ty).is_some() && p.path.segments.len() == 1 { continue; }
 284                                                 if p.qself.is_some() { return false; }
 285                                                 if p.path.leading_colon.is_some() { return false; }
 286                                                 let mut p_iter = p.path.segments.iter();
 287                                                 let p_ident = &p_iter.next().unwrap().ident;
 288                                                 if let Some(gen) = new_typed_generics.get_mut(p_ident) {
 289                                                         if gen.is_some() { return false; }
 290                                                         if &format!("{}", p_iter.next().unwrap().ident) != "Target" {return false; }
 291
 292                                                         let mut non_lifetimes_processed = false;
 293                                                         for bound in t.bounds.iter() {
 294                                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
 295                                                                         if let Some(id) = trait_bound.path.get_ident() {
 296                                                                                 if format!("{}", id) == "Sized" { continue; }
 297                                                                         }
 298                                                                         if non_lifetimes_processed { return false; }
 299                                                                         non_lifetimes_processed = true;
 300                                                                         assert_simple_bound(&trait_bound);
 301                                                                         let resolved = types.resolve_path(&trait_bound.path, None);
 302                                                                         let ty = syn::Type::Path(syn::TypePath {
 303                                                                                 qself: None, path: string_path_to_syn_path(&resolved)
 304                                                                         });
 305                                                                         let ref_ty = parse_quote!(&#ty);
 306                                                                         let mut_ref_ty = parse_quote!(&mut #ty);
 307                                                                         if types.crate_types.traits.get(&resolved).is_some() {
 308                                                                                 self.default_generics.insert(p_ident, (ty, ref_ty, mut_ref_ty));
 309                                                                         } else {
 310                                                                                 self.default_generics.insert(p_ident, (ref_ty.clone(), ref_ty, mut_ref_ty));
 311                                                                         }
 312
 313                                                                         *gen = Some(resolved);
 314                                                                 }
 315                                                         }
 316                                                 } else { return false; }
 317                                         } else { return false; }
 318                                 }
 319                         }
 320                 }
 321                 for (key, value) in new_typed_generics.drain() {
 322                         if let Some(v) = value {
 323                                 assert!(self.typed_generics.insert(key, v).is_none());
 324                         } else { return false; }
 325                 }
 326                 true
 327         }
 328
 329         /// Learn the generics in generics in the current context, given a TypeResolver.
 330         pub fn learn_generics<'b, 'c>(&mut self, generics: &'a syn::Generics, types: &'b TypeResolver<'a, 'c>) -> bool {
 331                 self.learn_generics_with_impls(generics, &syn::PathArguments::None, types)
 332         }
 333
 334         /// Learn the associated types from the trait in the current context.
 335         pub fn learn_associated_types<'b, 'c>(&mut self, t: &'a syn::ItemTrait, types: &'b TypeResolver<'a, 'c>) {
 336                 for item in t.items.iter() {
 337                         match item {
 338                                 &syn::TraitItem::Type(ref t) => {
 339                                         if t.default.is_some() || t.generics.lt_token.is_some() { unimplemented!(); }
 340                                         let mut bounds_iter = t.bounds.iter();
 341                                         loop {
 342                                                 match bounds_iter.next().unwrap() {
 343                                                         syn::TypeParamBound::Trait(tr) => {
 344                                                                 assert_simple_bound(&tr);
 345                                                                 if let Some(path) = types.maybe_resolve_path(&tr.path, None) {
 346                                                                         if types.skip_path(&path) { continue; }
 347                                                                         // In general we handle Deref<Target=X> as if it were just X (and
 348                                                                         // implement Deref<Target=Self> for relevant types). We don't
 349                                                                         // bother to implement it for associated types, however, so we just
 350                                                                         // ignore such bounds.
 351                                                                         if path != "std::ops::Deref" && path != "core::ops::Deref" &&
 352                                                                         path != "std::ops::DerefMut" && path != "core::ops::DerefMut" {
 353                                                                                 self.typed_generics.insert(&t.ident, path);
 354                                                                         } else {
 355                                                                                 let last_seg_args = &tr.path.segments.last().unwrap().arguments;
 356                                                                                 if let syn::PathArguments::AngleBracketed(args) = last_seg_args {
 357                                                                                         assert_eq!(args.args.len(), 1);
 358                                                                                         if let syn::GenericArgument::Binding(binding) = &args.args[0] {
 359                                                                                                 assert_eq!(format!("{}", binding.ident), "Target");
 360                                                                                                 if let syn::Type::Path(p) = &binding.ty {
 361                                                                                                         // Note that we are assuming the order of type
 362                                                                                                         // declarations here, but that should be easy
 363                                                                                                         // to handle.
 364                                                                                                         let real_path = self.maybe_resolve_path(&p.path).unwrap();
 365                                                                                                         self.typed_generics.insert(&t.ident, real_path.clone());
 366                                                                                                 } else { unimplemented!(); }
 367                                                                                         } else { unimplemented!(); }
 368                                                                                 } else { unimplemented!(); }
 369                                                                         }
 370                                                                 } else { unimplemented!(); }
 371                                                                 for bound in bounds_iter {
 372                                                                         if let syn::TypeParamBound::Trait(t) = bound {
 373                                                                                 // We only allow for `?Sized` here.
 374                                                                                 assert_eq!(t.path.segments.len(), 1);
 375                                                                                 assert_eq!(format!("{}", t.path.segments[0].ident), "Sized");
 376                                                                         }
 377                                                                 }
 378                                                                 break;
 379                                                         },
 380                                                         syn::TypeParamBound::Lifetime(_) => {},
 381                                                 }
 382                                         }
 383                                 },
 384                                 _ => {},
 385                         }
 386                 }
 387         }
 388
 389         /// Attempt to resolve a Path as a generic parameter and return the full path. as both a string
 390         /// and syn::Path.
 391         pub fn maybe_resolve_path<'b>(&'b self, path: &syn::Path) -> Option<&'b String> {
 392                 if let Some(ident) = path.get_ident() {
 393                         if let Some(ty) = &self.self_ty {
 394                                 if format!("{}", ident) == "Self" {
 395                                         return Some(&ty);
 396                                 }
 397                         }
 398                         if let Some(res) = self.typed_generics.get(ident) {
 399                                 return Some(res);
 400                         }
 401                 } else {
 402                         // Associated types are usually specified as "Self::Generic", so we check for that
 403                         // explicitly here.
 404                         let mut it = path.segments.iter();
 405                         if path.segments.len() == 2 && format!("{}", it.next().unwrap().ident) == "Self" {
 406                                 let ident = &it.next().unwrap().ident;
 407                                 if let Some(res) = self.typed_generics.get(ident) {
 408                                         return Some(res);
 409                                 }
 410                         }
 411                 }
 412                 if let Some(parent) = self.parent {
 413                         parent.maybe_resolve_path(path)
 414                 } else {
 415                         None
 416                 }
 417         }
 418 }
 419
 420 pub trait ResolveType<'a> { fn resolve_type(&'a self, ty: &'a syn::Type) -> &'a syn::Type; }
 421 impl<'a, 'b, 'c: 'a + 'b> ResolveType<'c> for Option<&GenericTypes<'a, 'b>> {
 422         fn resolve_type(&'c self, ty: &'c syn::Type) -> &'c syn::Type {
 423                 if let Some(us) = self {
 424                         match ty {
 425                                 syn::Type::Path(p) => {
 426                                         if let Some(ident) = p.path.get_ident() {
 427                                                 if let Some((ty, _, _)) = us.default_generics.get(ident) {
 428                                                         return self.resolve_type(ty);
 429                                                 }
 430                                         }
 431                                 },
 432                                 syn::Type::Reference(syn::TypeReference { elem, mutability, .. }) => {
 433                                         if let syn::Type::Path(p) = &**elem {
 434                                                 if let Some(ident) = p.path.get_ident() {
 435                                                         if let Some((_, refty, mut_ref_ty)) = us.default_generics.get(ident) {
 436                                                                 if mutability.is_some() {
 437                                                                         return self.resolve_type(mut_ref_ty);
 438                                                                 } else {
 439                                                                         return self.resolve_type(refty);
 440                                                                 }
 441                                                         }
 442                                                 }
 443                                         }
 444                                 }
 445                                 _ => {},
 446                         }
 447                         us.parent.resolve_type(ty)
 448                 } else { ty }
 449         }
 450 }
 451
 452 #[derive(Clone, PartialEq)]
 453 // The type of declaration and the object itself
 454 pub enum DeclType<'a> {
 455         MirroredEnum,
 456         Trait(&'a syn::ItemTrait),
 457         StructImported { generics: &'a syn::Generics  },
 458         StructIgnored,
 459         EnumIgnored { generics: &'a syn::Generics },
 460 }
 461
 462 pub struct ImportResolver<'mod_lifetime, 'crate_lft: 'mod_lifetime> {
 463         pub crate_name: &'mod_lifetime str,
 464         library: &'crate_lft FullLibraryAST,
 465         module_path: &'mod_lifetime str,
 466         imports: HashMap<syn::Ident, (String, syn::Path)>,
 467         declared: HashMap<syn::Ident, DeclType<'crate_lft>>,
 468         priv_modules: HashSet<syn::Ident>,
 469 }
 470 impl<'mod_lifetime, 'crate_lft: 'mod_lifetime> ImportResolver<'mod_lifetime, 'crate_lft> {
 471         fn walk_use_intern<F: FnMut(syn::Ident, (String, syn::Path))>(
 472                 crate_name: &str, module_path: &str, dependencies: &HashSet<syn::Ident>, u: &syn::UseTree,
 473                 partial_path: &str,
 474                 mut path: syn::punctuated::Punctuated<syn::PathSegment, syn::token::Colon2>, handle_use: &mut F
 475         ) {
 476                 let new_path;
 477                 macro_rules! push_path {
 478                         ($ident: expr, $path_suffix: expr) => {
 479                                 if partial_path == "" && format!("{}", $ident) == "super" {
 480                                         let mut mod_iter = module_path.rsplitn(2, "::");
 481                                         mod_iter.next().unwrap();
 482                                         let super_mod = mod_iter.next().unwrap();
 483                                         new_path = format!("{}{}", super_mod, $path_suffix);
 484                                         assert_eq!(path.len(), 0);
 485                                         for module in super_mod.split("::") {
 486                                                 path.push(syn::PathSegment { ident: syn::Ident::new(module, Span::call_site()), arguments: syn::PathArguments::None });
 487                                         }
 488                                 } else if partial_path == "" && format!("{}", $ident) == "self" {
 489                                         new_path = format!("{}{}", module_path, $path_suffix);
 490                                         for module in module_path.split("::") {
 491                                                 path.push(syn::PathSegment { ident: syn::Ident::new(module, Span::call_site()), arguments: syn::PathArguments::None });
 492                                         }
 493                                 } else if partial_path == "" && format!("{}", $ident) == "crate" {
 494                                         new_path = format!("{}{}", crate_name, $path_suffix);
 495                                         let crate_name_ident = format_ident!("{}", crate_name);
 496                                         path.push(parse_quote!(#crate_name_ident));
 497                                 } else if partial_path == "" && !dependencies.contains(&$ident) {
 498                                         new_path = format!("{}::{}{}", module_path, $ident, $path_suffix);
 499                                         for module in module_path.split("::") {
 500                                                 path.push(syn::PathSegment { ident: syn::Ident::new(module, Span::call_site()), arguments: syn::PathArguments::None });
 501                                         }
 502                                         let ident_str = format_ident!("{}", $ident);
 503                                         path.push(parse_quote!(#ident_str));
 504                                 } else if format!("{}", $ident) == "self" {
 505                                         let mut path_iter = partial_path.rsplitn(2, "::");
 506                                         path_iter.next().unwrap();
 507                                         new_path = path_iter.next().unwrap().to_owned();
 508                                 } else {
 509                                         new_path = format!("{}{}{}", partial_path, $ident, $path_suffix);
 510                                 }
 511                                 let ident = &$ident;
 512                                 path.push(parse_quote!(#ident));
 513                         }
 514                 }
 515                 match u {
 516                         syn::UseTree::Path(p) => {
 517                                 push_path!(p.ident, "::");
 518                                 Self::walk_use_intern(crate_name, module_path, dependencies, &p.tree, &new_path, path, handle_use);
 519                         },
 520                         syn::UseTree::Name(n) => {
 521                                 push_path!(n.ident, "");
 522                                 let imported_ident = syn::Ident::new(new_path.rsplitn(2, "::").next().unwrap(), Span::call_site());
 523                                 handle_use(imported_ident, (new_path, syn::Path { leading_colon: Some(syn::Token![::](Span::call_site())), segments: path }));
 524                         },
 525                         syn::UseTree::Group(g) => {
 526                                 for i in g.items.iter() {
 527                                         Self::walk_use_intern(crate_name, module_path, dependencies, i, partial_path, path.clone(), handle_use);
 528                                 }
 529                         },
 530                         syn::UseTree::Rename(r) => {
 531                                 push_path!(r.ident, "");
 532                                 handle_use(r.rename.clone(), (new_path, syn::Path { leading_colon: Some(syn::Token![::](Span::call_site())), segments: path }));
 533                         },
 534                         syn::UseTree::Glob(_) => {
 535                                 eprintln!("Ignoring * use for {} - this may result in resolution failures", partial_path);
 536                         },
 537                 }
 538         }
 539
 540         fn process_use_intern(crate_name: &str, module_path: &str, dependencies: &HashSet<syn::Ident>,
 541                 imports: &mut HashMap<syn::Ident, (String, syn::Path)>, u: &syn::UseTree, partial_path: &str,
 542                 path: syn::punctuated::Punctuated<syn::PathSegment, syn::token::Colon2>
 543         ) {
 544                 Self::walk_use_intern(crate_name, module_path, dependencies, u, partial_path, path,
 545                         &mut |k, v| { imports.insert(k, v); });
 546         }
 547
 548         fn process_use(crate_name: &str, module_path: &str, dependencies: &HashSet<syn::Ident>, imports: &mut HashMap<syn::Ident, (String, syn::Path)>, u: &syn::ItemUse) {
 549                 if u.leading_colon.is_some() { eprintln!("Ignoring leading-colon use!"); return; }
 550                 Self::process_use_intern(crate_name, module_path, dependencies, imports, &u.tree, "", syn::punctuated::Punctuated::new());
 551         }
 552
 553         fn insert_primitive(imports: &mut HashMap<syn::Ident, (String, syn::Path)>, id: &str) {
 554                 let ident = format_ident!("{}", id);
 555                 let path = parse_quote!(#ident);
 556                 imports.insert(ident, (id.to_owned(), path));
 557         }
 558
 559         pub fn new(crate_name: &'mod_lifetime str, library: &'crate_lft FullLibraryAST, module_path: &'mod_lifetime str, contents: &'crate_lft [syn::Item]) -> Self {
 560                 Self::from_borrowed_items(crate_name, library, module_path, &contents.iter().map(|a| a).collect::<Vec<_>>())
 561         }
 562         pub fn from_borrowed_items(crate_name: &'mod_lifetime str, library: &'crate_lft FullLibraryAST, module_path: &'mod_lifetime str, contents: &[&'crate_lft syn::Item]) -> Self {
 563                 let mut imports = HashMap::new();
 564                 // Add primitives to the "imports" list:
 565                 Self::insert_primitive(&mut imports, "bool");
 566                 Self::insert_primitive(&mut imports, "u128");
 567                 Self::insert_primitive(&mut imports, "i64");
 568                 Self::insert_primitive(&mut imports, "f64");
 569                 Self::insert_primitive(&mut imports, "u64");
 570                 Self::insert_primitive(&mut imports, "u32");
 571                 Self::insert_primitive(&mut imports, "u16");
 572                 Self::insert_primitive(&mut imports, "u8");
 573                 Self::insert_primitive(&mut imports, "usize");
 574                 Self::insert_primitive(&mut imports, "str");
 575                 Self::insert_primitive(&mut imports, "String");
 576
 577                 // These are here to allow us to print native Rust types in trait fn impls even if we don't
 578                 // have C mappings:
 579                 Self::insert_primitive(&mut imports, "Result");
 580                 Self::insert_primitive(&mut imports, "Vec");
 581                 Self::insert_primitive(&mut imports, "Option");
 582
 583                 let mut declared = HashMap::new();
 584                 let mut priv_modules = HashSet::new();
 585
 586                 for item in contents.iter() {
 587                         match item {
 588                                 syn::Item::Use(u) => Self::process_use(crate_name, module_path, &library.dependencies, &mut imports, &u),
 589                                 syn::Item::Struct(s) => {
 590                                         if let syn::Visibility::Public(_) = s.vis {
 591                                                 match export_status(&s.attrs) {
 592                                                         ExportStatus::Export => { declared.insert(s.ident.clone(), DeclType::StructImported { generics: &s.generics }); },
 593                                                         ExportStatus::NoExport => { declared.insert(s.ident.clone(), DeclType::StructIgnored); },
 594                                                         ExportStatus::TestOnly => continue,
 595                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) should only appear on traits!"),
 596                                                 }
 597                                         }
 598                                 },
 599                                 syn::Item::Type(t) if export_status(&t.attrs) == ExportStatus::Export => {
 600                                         if let syn::Visibility::Public(_) = t.vis {
 601                                                 declared.insert(t.ident.clone(), DeclType::StructImported { generics: &t.generics });
 602                                         }
 603                                 },
 604                                 syn::Item::Enum(e) => {
 605                                         if let syn::Visibility::Public(_) = e.vis {
 606                                                 match export_status(&e.attrs) {
 607                                                         ExportStatus::Export if is_enum_opaque(e) => { declared.insert(e.ident.clone(), DeclType::EnumIgnored { generics: &e.generics }); },
 608                                                         ExportStatus::Export => { declared.insert(e.ident.clone(), DeclType::MirroredEnum); },
 609                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) should only appear on traits!"),
 610                                                         _ => continue,
 611                                                 }
 612                                         }
 613                                 },
 614                                 syn::Item::Trait(t) => {
 615                                         if let syn::Visibility::Public(_) = t.vis {
 616                                                 declared.insert(t.ident.clone(), DeclType::Trait(t));
 617                                         }
 618                                 },
 619                                 syn::Item::Mod(m) => {
 620                                         priv_modules.insert(m.ident.clone());
 621                                 },
 622                                 _ => {},
 623                         }
 624                 }
 625
 626                 Self { crate_name, library, module_path, imports, declared, priv_modules }
 627         }
 628
 629         pub fn maybe_resolve_declared(&self, id: &syn::Ident) -> Option<&DeclType<'crate_lft>> {
 630                 self.declared.get(id)
 631         }
 632
 633         pub fn maybe_resolve_ident(&self, id: &syn::Ident) -> Option<String> {
 634                 if let Some((imp, _)) = self.imports.get(id) {
 635                         Some(imp.clone())
 636                 } else if self.declared.get(id).is_some() {
 637                         Some(self.module_path.to_string() + "::" + &format!("{}", id))
 638                 } else { None }
 639         }
 640
 641         fn maybe_resolve_imported_path(&self, p: &syn::Path, generics: Option<&GenericTypes>) -> Option<String> {
 642                 if let Some(gen_types) = generics {
 643                         if let Some(resp) = gen_types.maybe_resolve_path(p) {
 644                                 return Some(resp.clone());
 645                         }
 646                 }
 647
 648                 if p.leading_colon.is_some() {
 649                         let mut res: String = p.segments.iter().enumerate().map(|(idx, seg)| {
 650                                 format!("{}{}", if idx == 0 { "" } else { "::" }, seg.ident)
 651                         }).collect();
 652                         let firstseg = p.segments.iter().next().unwrap();
 653                         if !self.library.dependencies.contains(&firstseg.ident) {
 654                                 res = self.crate_name.to_owned() + "::" + &res;
 655                         }
 656                         Some(res)
 657                 } else if let Some(id) = p.get_ident() {
 658                         self.maybe_resolve_ident(id)
 659                 } else {
 660                         if p.segments.len() == 1 {
 661                                 let seg = p.segments.iter().next().unwrap();
 662                                 return self.maybe_resolve_ident(&seg.ident);
 663                         }
 664                         let mut seg_iter = p.segments.iter();
 665                         let first_seg = seg_iter.next().unwrap();
 666                         let remaining: String = seg_iter.map(|seg| {
 667                                 format!("::{}", seg.ident)
 668                         }).collect();
 669                         let first_seg_str = format!("{}", first_seg.ident);
 670                         if let Some((imp, _)) = self.imports.get(&first_seg.ident) {
 671                                 if remaining != "" {
 672                                         Some(imp.clone() + &remaining)
 673                                 } else {
 674                                         Some(imp.clone())
 675                                 }
 676                         } else if let Some(_) = self.priv_modules.get(&first_seg.ident) {
 677                                 Some(format!("{}::{}{}", self.module_path, first_seg.ident, remaining))
 678                         } else if first_seg_is_stdlib(&first_seg_str) || self.library.dependencies.contains(&first_seg.ident) {
 679                                 Some(first_seg_str + &remaining)
 680                         } else if first_seg_str == "crate" {
 681                                 Some(self.crate_name.to_owned() + &remaining)
 682                         } else if self.library.modules.get(&format!("{}::{}", self.module_path, first_seg.ident)).is_some() {
 683                                 Some(format!("{}::{}{}", self.module_path, first_seg.ident, remaining))
 684                         } else { None }
 685                 }
 686         }
 687
 688         pub fn maybe_resolve_path(&self, p: &syn::Path, generics: Option<&GenericTypes>) -> Option<String> {
 689                 self.maybe_resolve_imported_path(p, generics).map(|mut path| {
 690                         if path == "core::ops::Deref" || path == "core::ops::DerefMut" {
 691                                 let last_seg = p.segments.last().unwrap();
 692                                 if let syn::PathArguments::AngleBracketed(args) = &last_seg.arguments {
 693                                         assert_eq!(args.args.len(), 1);
 694                                         if let syn::GenericArgument::Binding(binding) = &args.args[0] {
 695                                                 if let syn::Type::Path(p) = &binding.ty {
 696                                                         if let Some(inner_ty) = self.maybe_resolve_path(&p.path, generics) {
 697                                                                 let mut module_riter = inner_ty.rsplitn(2, "::");
 698                                                                 let ty_ident = module_riter.next().unwrap();
 699                                                                 let module_name = module_riter.next().unwrap();
 700                                                                 let module = self.library.modules.get(module_name).unwrap();
 701                                                                 for item in module.items.iter() {
 702                                                                         match item {
 703                                                                                 syn::Item::Trait(t) => {
 704                                                                                         if t.ident == ty_ident {
 705                                                                                                 path = inner_ty;
 706                                                                                                 break;
 707                                                                                         }
 708                                                                                 },
 709                                                                                 _ => {}
 710                                                                         }
 711                                                                 }
 712                                                         }
 713                                                 } else { unimplemented!(); }
 714                                         } else { unimplemented!(); }
 715                                 }
 716                         }
 717                         loop {
 718                                 // Now that we've resolved the path to the path as-imported, check whether the path
 719                                 // is actually a pub(.*) use statement and map it to the real path.
 720                                 let path_tmp = path.clone();
 721                                 let crate_name = path_tmp.splitn(2, "::").next().unwrap();
 722                                 let mut module_riter = path_tmp.rsplitn(2, "::");
 723                                 let obj = module_riter.next().unwrap();
 724                                 if let Some(module_path) = module_riter.next() {
 725                                         if let Some(m) = self.library.modules.get(module_path) {
 726                                                 for item in m.items.iter() {
 727                                                         if let syn::Item::Use(syn::ItemUse { vis, tree, .. }) = item {
 728                                                                 match vis {
 729                                                                         syn::Visibility::Public(_)|
 730                                                                         syn::Visibility::Crate(_)|
 731                                                                         syn::Visibility::Restricted(_) => {
 732                                                                                 Self::walk_use_intern(crate_name, module_path,
 733                                                                                         &self.library.dependencies, tree, "",
 734                                                                                         syn::punctuated::Punctuated::new(), &mut |ident, (use_path, _)| {
 735                                                                                                 if format!("{}", ident) == obj {
 736                                                                                                         path = use_path;
 737                                                                                                 }
 738                                                                                 });
 739                                                                         },
 740                                                                         syn::Visibility::Inherited => {},
 741                                                                 }
 742                                                         }
 743                                                 }
 744                                         }
 745                                 }
 746                                 break;
 747                         }
 748                         path
 749                 })
 750         }
 751
 752         /// Map all the Paths in a Type into absolute paths given a set of imports (generated via process_use_intern)
 753         pub fn resolve_imported_refs(&self, mut ty: syn::Type) -> syn::Type {
 754                 match &mut ty {
 755                         syn::Type::Path(p) => {
 756                                 if p.path.segments.len() != 1 { unimplemented!(); }
 757                                 let mut args = p.path.segments[0].arguments.clone();
 758                                 if let syn::PathArguments::AngleBracketed(ref mut generics) = &mut args {
 759                                         for arg in generics.args.iter_mut() {
 760                                                 if let syn::GenericArgument::Type(ref mut t) = arg {
 761                                                         *t = self.resolve_imported_refs(t.clone());
 762                                                 }
 763                                         }
 764                                 }
 765                                 if let Some((_, newpath)) = self.imports.get(single_ident_generic_path_to_ident(&p.path).unwrap()) {
 766                                         p.path = newpath.clone();
 767                                 }
 768                                 p.path.segments[0].arguments = args;
 769                         },
 770                         syn::Type::Reference(r) => {
 771                                 r.elem = Box::new(self.resolve_imported_refs((*r.elem).clone()));
 772                         },
 773                         syn::Type::Slice(s) => {
 774                                 s.elem = Box::new(self.resolve_imported_refs((*s.elem).clone()));
 775                         },
 776                         syn::Type::Tuple(t) => {
 777                                 for e in t.elems.iter_mut() {
 778                                         *e = self.resolve_imported_refs(e.clone());
 779                                 }
 780                         },
 781                         _ => unimplemented!(),
 782                 }
 783                 ty
 784         }
 785 }
 786
 787 // templates_defined is walked to write the C++ header, so if we use the default hashing it get
 788 // reordered on each genbindings run. Instead, we use SipHasher (which defaults to 0-keys) so that
 789 // the sorting is stable across runs. It is deprecated, but the "replacement" doesn't actually
 790 // accomplish the same goals, so we just ignore it.
 791 #[allow(deprecated)]
 792 pub type NonRandomHash = hash::BuildHasherDefault<hash::SipHasher>;
 793
 794 /// A public module
 795 pub struct ASTModule {
 796         pub attrs: Vec<syn::Attribute>,
 797         pub items: Vec<syn::Item>,
 798         pub submods: Vec<String>,
 799 }
 800 /// A struct containing the syn::File AST for each file in the crate.
 801 pub struct FullLibraryAST {
 802         pub modules: HashMap<String, ASTModule, NonRandomHash>,
 803         pub dependencies: HashSet<syn::Ident>,
 804 }
 805 impl FullLibraryAST {
 806         fn load_module(&mut self, module: String, attrs: Vec<syn::Attribute>, mut items: Vec<syn::Item>) {
 807                 let mut non_mod_items = Vec::with_capacity(items.len());
 808                 let mut submods = Vec::with_capacity(items.len());
 809                 for item in items.drain(..) {
 810                         match item {
 811                                 syn::Item::Mod(m) if m.content.is_some() => {
 812                                         if export_status(&m.attrs) == ExportStatus::Export {
 813                                                 if let syn::Visibility::Public(_) = m.vis {
 814                                                         let modident = format!("{}", m.ident);
 815                                                         let modname = if module != "" {
 816                                                                 module.clone() + "::" + &modident
 817                                                         } else {
 818                                                                 self.dependencies.insert(m.ident);
 819                                                                 modident.clone()
 820                                                         };
 821                                                         self.load_module(modname, m.attrs, m.content.unwrap().1);
 822                                                         submods.push(modident);
 823                                                 } else {
 824                                                         non_mod_items.push(syn::Item::Mod(m));
 825                                                 }
 826                                         }
 827                                 },
 828                                 syn::Item::Mod(_) => panic!("--pretty=expanded output should never have non-body modules"),
 829                                 syn::Item::ExternCrate(c) => {
 830                                         if export_status(&c.attrs) == ExportStatus::Export {
 831                                                 self.dependencies.insert(c.ident);
 832                                         }
 833                                 },
 834                                 _ => { non_mod_items.push(item); }
 835                         }
 836                 }
 837                 self.modules.insert(module, ASTModule { attrs, items: non_mod_items, submods });
 838         }
 839
 840         pub fn load_lib(lib: syn::File) -> Self {
 841                 assert_eq!(export_status(&lib.attrs), ExportStatus::Export);
 842                 let mut res = Self { modules: HashMap::default(), dependencies: HashSet::new() };
 843                 res.load_module("".to_owned(), lib.attrs, lib.items);
 844                 res
 845         }
 846 }
 847
 848 /// List of manually-generated types which are clonable
 849 fn initial_clonable_types() -> HashSet<String> {
 850         let mut res = HashSet::new();
 851         res.insert("crate::c_types::U5".to_owned());
 852         res.insert("crate::c_types::U128".to_owned());
 853         res.insert("crate::c_types::FourBytes".to_owned());
 854         res.insert("crate::c_types::TwelveBytes".to_owned());
 855         res.insert("crate::c_types::SixteenBytes".to_owned());
 856         res.insert("crate::c_types::TwentyBytes".to_owned());
 857         res.insert("crate::c_types::ThirtyTwoBytes".to_owned());
 858         res.insert("crate::c_types::EightU16s".to_owned());
 859         res.insert("crate::c_types::SecretKey".to_owned());
 860         res.insert("crate::c_types::PublicKey".to_owned());
 861         res.insert("crate::c_types::Transaction".to_owned());
 862         res.insert("crate::c_types::Witness".to_owned());
 863         res.insert("crate::c_types::WitnessVersion".to_owned());
 864         res.insert("crate::c_types::TxIn".to_owned());
 865         res.insert("crate::c_types::TxOut".to_owned());
 866         res.insert("crate::c_types::Signature".to_owned());
 867         res.insert("crate::c_types::RecoverableSignature".to_owned());
 868         res.insert("crate::c_types::BigEndianScalar".to_owned());
 869         res.insert("crate::c_types::Bech32Error".to_owned());
 870         res.insert("crate::c_types::Secp256k1Error".to_owned());
 871         res.insert("crate::c_types::IOError".to_owned());
 872         res.insert("crate::c_types::Error".to_owned());
 873         res.insert("crate::c_types::Str".to_owned());
 874
 875         // Because some types are manually-mapped to CVec_u8Z we may end up checking if its clonable
 876         // before we ever get to constructing the type fully via
 877         // `write_c_mangled_container_path_intern` (which will add it here too), so we have to manually
 878         // add it on startup.
 879         res.insert("crate::c_types::derived::CVec_u8Z".to_owned());
 880         res
 881 }
 882
 883 /// Top-level struct tracking everything which has been defined while walking the crate.
 884 pub struct CrateTypes<'a> {
 885         /// This may contain structs or enums, but only when either is mapped as
 886         /// struct X { inner: *mut originalX, .. }
 887         pub opaques: HashMap<String, (&'a syn::Ident, &'a syn::Generics)>,
 888         /// structs that weren't exposed
 889         pub priv_structs: HashMap<String, &'a syn::Generics>,
 890         /// Enums which are mapped as C enums with conversion functions
 891         pub mirrored_enums: HashMap<String, &'a syn::ItemEnum>,
 892         /// Traits which are mapped as a pointer + jump table
 893         pub traits: HashMap<String, &'a syn::ItemTrait>,
 894         /// Aliases from paths to some other Type
 895         pub type_aliases: HashMap<String, syn::Type>,
 896         /// Value is an alias to Key (maybe with some generics)
 897         pub reverse_alias_map: HashMap<String, Vec<(String, syn::PathArguments)>>,
 898         /// Template continer types defined, map from mangled type name -> whether a destructor fn
 899         /// exists.
 900         ///
 901         /// This is used at the end of processing to make C++ wrapper classes
 902         pub templates_defined: RefCell<HashMap<String, bool, NonRandomHash>>,
 903         /// The output file for any created template container types, written to as we find new
 904         /// template containers which need to be defined.
 905         template_file: RefCell<&'a mut File>,
 906         /// Set of containers which are clonable
 907         clonable_types: RefCell<HashSet<String>>,
 908         /// Key impls Value
 909         pub trait_impls: HashMap<String, Vec<String>>,
 910         /// Value impls Key
 911         pub traits_impld: HashMap<String, Vec<String>>,
 912         /// The full set of modules in the crate(s)
 913         pub lib_ast: &'a FullLibraryAST,
 914 }
 915
 916 impl<'a> CrateTypes<'a> {
 917         pub fn new(template_file: &'a mut File, libast: &'a FullLibraryAST) -> Self {
 918                 CrateTypes {
 919                         opaques: HashMap::new(), mirrored_enums: HashMap::new(), traits: HashMap::new(),
 920                         type_aliases: HashMap::new(), reverse_alias_map: HashMap::new(),
 921                         templates_defined: RefCell::new(HashMap::default()), priv_structs: HashMap::new(),
 922                         clonable_types: RefCell::new(initial_clonable_types()),
 923                         trait_impls: HashMap::new(), traits_impld: HashMap::new(),
 924                         template_file: RefCell::new(template_file), lib_ast: &libast,
 925                 }
 926         }
 927         pub fn set_clonable(&self, object: String) {
 928                 self.clonable_types.borrow_mut().insert(object);
 929         }
 930         pub fn is_clonable(&self, object: &str) -> bool {
 931                 self.clonable_types.borrow().contains(object)
 932         }
 933         pub fn write_new_template(&self, mangled_container: String, has_destructor: bool, created_container: &[u8]) {
 934                 self.template_file.borrow_mut().write(created_container).unwrap();
 935                 self.templates_defined.borrow_mut().insert(mangled_container, has_destructor);
 936         }
 937 }
 938
 939 /// A struct which tracks resolving rust types into C-mapped equivalents, exists for one specific
 940 /// module but contains a reference to the overall CrateTypes tracking.
 941 pub struct TypeResolver<'mod_lifetime, 'crate_lft: 'mod_lifetime> {
 942         pub module_path: &'mod_lifetime str,
 943         pub crate_types: &'mod_lifetime CrateTypes<'crate_lft>,
 944         pub types: ImportResolver<'mod_lifetime, 'crate_lft>,
 945 }
 946
 947 /// Returned by write_empty_rust_val_check_suffix to indicate what type of dereferencing needs to
 948 /// happen to get the inner value of a generic.
 949 enum EmptyValExpectedTy {
 950         /// A type which has a flag for being empty (eg an array where we treat all-0s as empty).
 951         NonPointer,
 952         /// A Option mapped as a COption_*Z
 953         OptionType,
 954         /// A pointer which we want to convert to a reference.
 955         ReferenceAsPointer,
 956 }
 957
 958 #[derive(PartialEq)]
 959 /// Describes the appropriate place to print a general type-conversion string when converting a
 960 /// container.
 961 enum ContainerPrefixLocation {
 962         /// Prints a general type-conversion string prefix and suffix outside of the
 963         /// container-conversion strings.
 964         OutsideConv,
 965         /// Prints a general type-conversion string prefix and suffix inside of the
 966         /// container-conversion strings.
 967         PerConv,
 968         /// Does not print the usual type-conversion string prefix and suffix.
 969         NoPrefix,
 970 }
 971
 972 impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 973         pub fn new(module_path: &'a str, types: ImportResolver<'a, 'c>, crate_types: &'a CrateTypes<'c>) -> Self {
 974                 Self { module_path, types, crate_types }
 975         }
 976
 977         // *************************************************
 978         // *** Well know type and conversion definitions ***
 979         // *************************************************
 980
 981         /// Returns true we if can just skip passing this to C entirely
 982         pub fn skip_path(&self, full_path: &str) -> bool {
 983                 full_path == "bitcoin::secp256k1::Secp256k1" ||
 984                 full_path == "bitcoin::secp256k1::Signing" ||
 985                 full_path == "bitcoin::secp256k1::Verification"
 986         }
 987         /// Returns true we if can just skip passing this to C entirely
 988         fn no_arg_path_to_rust(&self, full_path: &str) -> &str {
 989                 if full_path == "bitcoin::secp256k1::Secp256k1" {
 990                         "secp256k1::global::SECP256K1"
 991                 } else { unimplemented!(); }
 992         }
 993
 994         /// Returns true if the object is a primitive and is mapped as-is with no conversion
 995         /// whatsoever.
 996         pub fn is_primitive(&self, full_path: &str) -> bool {
 997                 match full_path {
 998                         "bool" => true,
 999                         "i64" => true,
1000                         "f64" => true,
1001                         "u64" => true,
1002                         "u32" => true,
1003                         "u16" => true,
1004                         "u8" => true,
1005                         "usize" => true,
1006                         _ => false,
1007                 }
1008         }
1009         pub fn is_clonable(&self, ty: &str) -> bool {
1010                 if self.crate_types.is_clonable(ty) { return true; }
1011                 if self.is_primitive(ty) { return true; }
1012                 match ty {
1013                         "()" => true,
1014                         _ => false,
1015                 }
1016         }
1017         /// Gets the C-mapped type for types which are outside of the crate, or which are manually
1018         /// ignored by for some reason need mapping anyway.
1019         fn c_type_from_path<'b>(&self, full_path: &'b str, is_ref: bool, _ptr_for_ref: bool) -> Option<&'b str> {
1020                 if self.is_primitive(full_path) {
1021                         return Some(full_path);
1022                 }
1023                 match full_path {
1024                         // Note that no !is_ref types can map to an array because Rust and C's call semantics
1025                         // for arrays are different (https://github.com/eqrion/cbindgen/issues/528)
1026
1027                         "[u8; 32]" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
1028                         "[u8; 20]" if !is_ref => Some("crate::c_types::TwentyBytes"),
1029                         "[u8; 16]" if !is_ref => Some("crate::c_types::SixteenBytes"),
1030                         "[u8; 12]" if !is_ref => Some("crate::c_types::TwelveBytes"),
1031                         "[u8; 4]" if !is_ref => Some("crate::c_types::FourBytes"),
1032                         "[u8; 3]" if !is_ref => Some("crate::c_types::ThreeBytes"), // Used for RGB values
1033                         "[u16; 8]" if !is_ref => Some("crate::c_types::EightU16s"),
1034
1035                         "str" if is_ref => Some("crate::c_types::Str"),
1036                         "alloc::string::String"|"String" => Some("crate::c_types::Str"),
1037
1038                         "bitcoin::Address" => Some("crate::c_types::Str"),
1039
1040                         "std::time::Duration"|"core::time::Duration" => Some("u64"),
1041                         "std::time::SystemTime" => Some("u64"),
1042                         "std::io::Error"|"lightning::io::Error"|"lightning::io::ErrorKind" => Some("crate::c_types::IOError"),
1043                         "core::fmt::Arguments" if is_ref => Some("crate::c_types::Str"),
1044
1045                         "core::convert::Infallible" => Some("crate::c_types::NotConstructable"),
1046
1047                         "bitcoin::bech32::Error"|"bech32::Error"
1048                                 if !is_ref => Some("crate::c_types::Bech32Error"),
1049                         "bitcoin::secp256k1::Error"|"secp256k1::Error"
1050                                 if !is_ref => Some("crate::c_types::Secp256k1Error"),
1051
1052                         "core::num::ParseIntError" => Some("crate::c_types::Error"),
1053                         "core::str::Utf8Error" => Some("crate::c_types::Error"),
1054
1055                         "bitcoin::bech32::u5"|"bech32::u5" => Some("crate::c_types::U5"),
1056                         "u128" => Some("crate::c_types::U128"),
1057                         "core::num::NonZeroU8" => Some("u8"),
1058
1059                         "secp256k1::PublicKey"|"bitcoin::secp256k1::PublicKey" => Some("crate::c_types::PublicKey"),
1060                         "bitcoin::secp256k1::ecdsa::Signature" => Some("crate::c_types::Signature"),
1061                         "bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some("crate::c_types::RecoverableSignature"),
1062                         "bitcoin::secp256k1::SecretKey" if is_ref  => Some("*const [u8; 32]"),
1063                         "bitcoin::secp256k1::SecretKey" if !is_ref => Some("crate::c_types::SecretKey"),
1064                         "bitcoin::secp256k1::KeyPair" if !is_ref => Some("crate::c_types::SecretKey"),
1065                         "bitcoin::secp256k1::Scalar" if is_ref  => Some("*const crate::c_types::BigEndianScalar"),
1066                         "bitcoin::secp256k1::Scalar" if !is_ref => Some("crate::c_types::BigEndianScalar"),
1067                         "bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
1068
1069                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if is_ref => Some("crate::c_types::u8slice"),
1070                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if !is_ref => Some("crate::c_types::derived::CVec_u8Z"),
1071                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" => Some("crate::lightning::chain::transaction::OutPoint"),
1072                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" => Some("crate::c_types::Transaction"),
1073                         "bitcoin::Witness" => Some("crate::c_types::Witness"),
1074                         "bitcoin::TxIn"|"bitcoin::blockdata::transaction::TxIn" if !is_ref => Some("crate::c_types::TxIn"),
1075                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" => Some("crate::c_types::TxOut"),
1076                         "bitcoin::network::constants::Network" => Some("crate::bitcoin::network::Network"),
1077                         "bitcoin::util::address::WitnessVersion" => Some("crate::c_types::WitnessVersion"),
1078                         "bitcoin::blockdata::block::BlockHeader" if is_ref  => Some("*const [u8; 80]"),
1079                         "bitcoin::blockdata::block::Block" if is_ref  => Some("crate::c_types::u8slice"),
1080
1081                         "bitcoin::PackedLockTime"|"bitcoin::blockdata::locktime::PackedLockTime" => Some("u32"),
1082
1083                         "bitcoin::psbt::PartiallySignedTransaction" if !is_ref => Some("crate::c_types::derived::CVec_u8Z"),
1084
1085                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1086                         "bitcoin::hash_types::WPubkeyHash"|
1087                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1088                                 if !is_ref => Some("crate::c_types::TwentyBytes"),
1089                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1090                         "bitcoin::hash_types::WPubkeyHash"|
1091                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1092                                 if is_ref => Some("*const [u8; 20]"),
1093                         "bitcoin::hash_types::WScriptHash"
1094                                 if is_ref => Some("*const [u8; 32]"),
1095
1096                         // Newtypes that we just expose in their original form.
1097                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"|"bitcoin::blockdata::constants::ChainHash"
1098                                 if is_ref  => Some("*const [u8; 32]"),
1099                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"|"bitcoin::blockdata::constants::ChainHash"
1100                                 if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
1101                         "bitcoin::secp256k1::Message" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
1102                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1103                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1104                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1105                                 if is_ref => Some("*const [u8; 32]"),
1106                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1107                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1108                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1109                                 if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
1110
1111                         "lightning::io::Read" => Some("crate::c_types::u8slice"),
1112
1113                         _ => None,
1114                 }
1115         }
1116
1117         fn from_c_conversion_new_var_from_path<'b>(&self, _full_path: &str, _is_ref: bool) -> Option<(&'b str, &'b str)> {
1118                 None
1119         }
1120         fn from_c_conversion_prefix_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<String> {
1121                 if self.is_primitive(full_path) {
1122                         return Some("".to_owned());
1123                 }
1124                 match full_path {
1125                         "Vec" if !is_ref => Some("local_"),
1126                         "Result" if !is_ref => Some("local_"),
1127                         "Option" if is_ref => Some("&local_"),
1128                         "Option" => Some("local_"),
1129
1130                         "[u8; 32]" if is_ref => Some("unsafe { &*"),
1131                         "[u8; 32]" if !is_ref => Some(""),
1132                         "[u8; 20]" if !is_ref => Some(""),
1133                         "[u8; 16]" if !is_ref => Some(""),
1134                         "[u8; 12]" if !is_ref => Some(""),
1135                         "[u8; 4]" if !is_ref => Some(""),
1136                         "[u8; 3]" if !is_ref => Some(""),
1137                         "[u16; 8]" if !is_ref => Some(""),
1138
1139                         "[u8]" if is_ref => Some(""),
1140                         "[usize]" if is_ref => Some(""),
1141
1142                         "str" if is_ref => Some(""),
1143                         "alloc::string::String"|"String" => Some(""),
1144                         "std::io::Error"|"lightning::io::Error"|"lightning::io::ErrorKind" => Some(""),
1145                         // Note that we'll panic for String if is_ref, as we only have non-owned memory, we
1146                         // cannot create a &String.
1147
1148                         "core::convert::Infallible" => Some("panic!(\"You must never construct a NotConstructable! : "),
1149
1150                         "bitcoin::bech32::Error"|"bech32::Error" if !is_ref => Some(""),
1151                         "bitcoin::secp256k1::Error"|"secp256k1::Error" if !is_ref => Some(""),
1152
1153                         "core::num::ParseIntError" => Some("u8::from_str_radix(\" a\", 10).unwrap_err() /*"),
1154                         "core::str::Utf8Error" => Some("core::str::from_utf8(&[0xff]).unwrap_err() /*"),
1155
1156                         "std::time::Duration"|"core::time::Duration" => Some("core::time::Duration::from_secs("),
1157                         "std::time::SystemTime" => Some("(::std::time::SystemTime::UNIX_EPOCH + std::time::Duration::from_secs("),
1158
1159                         "bitcoin::bech32::u5"|"bech32::u5" => Some(""),
1160                         "u128" => Some(""),
1161                         "core::num::NonZeroU8" => Some("core::num::NonZeroU8::new("),
1162
1163                         "bitcoin::secp256k1::PublicKey"|"secp256k1::PublicKey" if is_ref => Some("&"),
1164                         "bitcoin::secp256k1::PublicKey"|"secp256k1::PublicKey" => Some(""),
1165                         "bitcoin::secp256k1::ecdsa::Signature" if is_ref => Some("&"),
1166                         "bitcoin::secp256k1::ecdsa::Signature" => Some(""),
1167                         "bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some(""),
1168                         "bitcoin::secp256k1::SecretKey" if is_ref => Some("&::bitcoin::secp256k1::SecretKey::from_slice(&unsafe { *"),
1169                         "bitcoin::secp256k1::SecretKey" if !is_ref => Some(""),
1170                         "bitcoin::secp256k1::KeyPair" if !is_ref => Some("::bitcoin::secp256k1::KeyPair::new("),
1171                         "bitcoin::secp256k1::Scalar" if is_ref => Some("&"),
1172                         "bitcoin::secp256k1::Scalar" if !is_ref => Some(""),
1173                         "bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some("::bitcoin::secp256k1::ecdh::SharedSecret::from_bytes("),
1174
1175                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if is_ref => Some("&::bitcoin::blockdata::script::Script::from(Vec::from("),
1176                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if !is_ref => Some("::bitcoin::blockdata::script::Script::from("),
1177                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" if is_ref => Some("&"),
1178                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" => Some(""),
1179                         "bitcoin::Witness" if is_ref => Some("&"),
1180                         "bitcoin::Witness" => Some(""),
1181                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" => Some("crate::c_types::C_to_bitcoin_outpoint("),
1182                         "bitcoin::TxIn"|"bitcoin::blockdata::transaction::TxIn" if !is_ref => Some(""),
1183                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(""),
1184                         "bitcoin::network::constants::Network" => Some(""),
1185                         "bitcoin::util::address::WitnessVersion" => Some(""),
1186                         "bitcoin::blockdata::block::BlockHeader" => Some("&::bitcoin::consensus::encode::deserialize(unsafe { &*"),
1187                         "bitcoin::blockdata::block::Block" if is_ref => Some("&::bitcoin::consensus::encode::deserialize("),
1188
1189                         "bitcoin::PackedLockTime"|"bitcoin::blockdata::locktime::PackedLockTime" => Some("::bitcoin::PackedLockTime("),
1190
1191                         "bitcoin::psbt::PartiallySignedTransaction" if !is_ref => Some("::bitcoin::consensus::encode::deserialize("),
1192
1193                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash" if !is_ref =>
1194                                 Some("bitcoin::hash_types::PubkeyHash::from_hash(bitcoin::hashes::Hash::from_inner("),
1195                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash" if is_ref =>
1196                                 Some("&bitcoin::hash_types::PubkeyHash::from_hash(bitcoin::hashes::Hash::from_inner(unsafe { *"),
1197                         "bitcoin::hash_types::WPubkeyHash" if is_ref =>
1198                                 Some("&bitcoin::hash_types::WPubkeyHash::from_hash(bitcoin::hashes::Hash::from_inner(unsafe { *"),
1199                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash" if !is_ref =>
1200                                 Some("bitcoin::hash_types::ScriptHash::from_hash(bitcoin::hashes::Hash::from_inner("),
1201                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash" if is_ref =>
1202                                 Some("&bitcoin::hash_types::ScriptHash::from_hash(bitcoin::hashes::Hash::from_inner(unsafe { *"),
1203                         "bitcoin::hash_types::WScriptHash" if is_ref =>
1204                                 Some("&bitcoin::hash_types::WScriptHash::from_hash(bitcoin::hashes::Hash::from_inner(unsafe { *"),
1205
1206                         // Newtypes that we just expose in their original form.
1207                         "bitcoin::hash_types::Txid" if is_ref => Some("&::bitcoin::hash_types::Txid::from_slice(&unsafe { &*"),
1208                         "bitcoin::hash_types::Txid" if !is_ref => Some("::bitcoin::hash_types::Txid::from_slice(&"),
1209                         "bitcoin::hash_types::BlockHash"|"bitcoin::BlockHash" => Some("::bitcoin::hash_types::BlockHash::from_slice(&"),
1210                         "bitcoin::blockdata::constants::ChainHash" => Some("::bitcoin::blockdata::constants::ChainHash::from(&"),
1211                         "lightning::ln::PaymentHash" if !is_ref => Some("::lightning::ln::PaymentHash("),
1212                         "lightning::ln::PaymentHash" if is_ref => Some("&::lightning::ln::PaymentHash(unsafe { *"),
1213                         "lightning::ln::PaymentPreimage" if !is_ref => Some("::lightning::ln::PaymentPreimage("),
1214                         "lightning::ln::PaymentPreimage" if is_ref => Some("&::lightning::ln::PaymentPreimage(unsafe { *"),
1215                         "lightning::ln::PaymentSecret" if !is_ref => Some("::lightning::ln::PaymentSecret("),
1216                         "lightning::ln::channelmanager::PaymentId" if !is_ref => Some("::lightning::ln::channelmanager::PaymentId("),
1217                         "lightning::ln::channelmanager::PaymentId" if is_ref=> Some("&::lightning::ln::channelmanager::PaymentId( unsafe { *"),
1218                         "lightning::ln::channelmanager::InterceptId" if !is_ref => Some("::lightning::ln::channelmanager::InterceptId("),
1219                         "lightning::ln::channelmanager::InterceptId" if is_ref=> Some("&::lightning::ln::channelmanager::InterceptId( unsafe { *"),
1220                         "lightning::sign::KeyMaterial" if !is_ref => Some("::lightning::sign::KeyMaterial("),
1221                         "lightning::sign::KeyMaterial" if is_ref=> Some("&::lightning::sign::KeyMaterial( unsafe { *"),
1222                         "lightning::chain::ClaimId" if !is_ref => Some("::lightning::chain::ClaimId("),
1223                         "lightning::chain::ClaimId" if is_ref=> Some("&::lightning::chain::ClaimId( unsafe { *"),
1224
1225                         // List of traits we map (possibly during processing of other files):
1226                         "lightning::io::Read" => Some("&mut "),
1227
1228                         _ => None,
1229                 }.map(|s| s.to_owned())
1230         }
1231         fn from_c_conversion_suffix_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<String> {
1232                 if self.is_primitive(full_path) {
1233                         return Some("".to_owned());
1234                 }
1235                 match full_path {
1236                         "Vec" if !is_ref => Some(""),
1237                         "Option" => Some(""),
1238                         "Result" if !is_ref => Some(""),
1239
1240                         "[u8; 32]" if is_ref => Some("}"),
1241                         "[u8; 32]" if !is_ref => Some(".data"),
1242                         "[u8; 20]" if !is_ref => Some(".data"),
1243                         "[u8; 16]" if !is_ref => Some(".data"),
1244                         "[u8; 12]" if !is_ref => Some(".data"),
1245                         "[u8; 4]" if !is_ref => Some(".data"),
1246                         "[u8; 3]" if !is_ref => Some(".data"),
1247                         "[u16; 8]" if !is_ref => Some(".data"),
1248
1249                         "[u8]" if is_ref => Some(".to_slice()"),
1250                         "[usize]" if is_ref => Some(".to_slice()"),
1251
1252                         "str" if is_ref => Some(".into_str()"),
1253                         "alloc::string::String"|"String" => Some(".into_string()"),
1254                         "std::io::Error"|"lightning::io::Error" => Some(".to_rust()"),
1255                         "lightning::io::ErrorKind" => Some(".to_rust_kind()"),
1256
1257                         "core::convert::Infallible" => Some("\")"),
1258
1259                         "bitcoin::bech32::Error"|"bech32::Error" if !is_ref => Some(".into_rust()"),
1260                         "bitcoin::secp256k1::Error"|"secp256k1::Error" if !is_ref => Some(".into_rust()"),
1261
1262                         "core::num::ParseIntError" => Some("*/"),
1263                         "core::str::Utf8Error" => Some("*/"),
1264
1265                         "std::time::Duration"|"core::time::Duration" => Some(")"),
1266                         "std::time::SystemTime" => Some("))"),
1267
1268                         "bitcoin::bech32::u5"|"bech32::u5" => Some(".into()"),
1269                         "u128" => Some(".into()"),
1270                         "core::num::NonZeroU8" => Some(").expect(\"Value must be non-zero\")"),
1271
1272                         "bitcoin::secp256k1::PublicKey"|"secp256k1::PublicKey" => Some(".into_rust()"),
1273                         "bitcoin::secp256k1::ecdsa::Signature" => Some(".into_rust()"),
1274                         "bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some(".into_rust()"),
1275                         "bitcoin::secp256k1::SecretKey" if !is_ref => Some(".into_rust()"),
1276                         "bitcoin::secp256k1::SecretKey" if is_ref => Some("}[..]).unwrap()"),
1277                         "bitcoin::secp256k1::KeyPair" if !is_ref => Some(".into_rust())"),
1278                         "bitcoin::secp256k1::Scalar" => Some(".into_rust()"),
1279                         "bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some(".data)"),
1280
1281                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if is_ref => Some(".to_slice()))"),
1282                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if !is_ref => Some(".into_rust())"),
1283                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" => Some(".into_bitcoin()"),
1284                         "bitcoin::Witness" => Some(".into_bitcoin()"),
1285                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" => Some(")"),
1286                         "bitcoin::TxIn"|"bitcoin::blockdata::transaction::TxIn" if !is_ref => Some(".into_rust()"),
1287                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(".into_rust()"),
1288                         "bitcoin::network::constants::Network" => Some(".into_bitcoin()"),
1289                         "bitcoin::util::address::WitnessVersion" => Some(".into()"),
1290                         "bitcoin::blockdata::block::BlockHeader" => Some(" }).unwrap()"),
1291                         "bitcoin::blockdata::block::Block" => Some(".to_slice()).unwrap()"),
1292
1293                         "bitcoin::PackedLockTime"|"bitcoin::blockdata::locktime::PackedLockTime" => Some(")"),
1294
1295                         "bitcoin::psbt::PartiallySignedTransaction" if !is_ref => Some(".as_slice()).expect(\"Invalid PSBT format\")"),
1296
1297                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1298                         "bitcoin::hash_types::WPubkeyHash"|"bitcoin::hash_types::WScriptHash"|
1299                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1300                                 if !is_ref => Some(".data))"),
1301                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1302                         "bitcoin::hash_types::WPubkeyHash"|"bitcoin::hash_types::WScriptHash"|
1303                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1304                                 if is_ref => Some(" }.clone()))"),
1305
1306                         // Newtypes that we just expose in their original form.
1307                         "bitcoin::hash_types::Txid" if is_ref => Some(" }[..]).unwrap()"),
1308                         "bitcoin::hash_types::Txid" => Some(".data[..]).unwrap()"),
1309                         "bitcoin::hash_types::BlockHash"|"bitcoin::BlockHash" if !is_ref => Some(".data[..]).unwrap()"),
1310                         "bitcoin::blockdata::constants::ChainHash" if !is_ref => Some(".data[..])"),
1311                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1312                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1313                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1314                                 if !is_ref => Some(".data)"),
1315                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1316                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1317                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1318                                 if is_ref => Some(" })"),
1319
1320                         // List of traits we map (possibly during processing of other files):
1321                         "lightning::io::Read" => Some(".to_reader()"),
1322
1323                         _ => None,
1324                 }.map(|s| s.to_owned())
1325         }
1326
1327         fn to_c_conversion_new_var_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<(&'b str, &'b str)> {
1328                 if self.is_primitive(full_path) {
1329                         return None;
1330                 }
1331                 match full_path {
1332                         "[u8]" if is_ref => Some(("crate::c_types::u8slice::from_slice(", ")")),
1333                         "[usize]" if is_ref => Some(("crate::c_types::usizeslice::from_slice(", ")")),
1334
1335                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some(("{ let mut s = [0u8; 80]; s[..].copy_from_slice(&::bitcoin::consensus::encode::serialize(", ")); s }")),
1336                         "bitcoin::blockdata::block::Block" if is_ref => Some(("::bitcoin::consensus::encode::serialize(", ")")),
1337                         "bitcoin::hash_types::Txid" => None,
1338
1339                         _ => None,
1340                 }.map(|s| s.to_owned())
1341         }
1342         fn to_c_conversion_inline_prefix_from_path(&self, full_path: &str, is_ref: bool, _ptr_for_ref: bool) -> Option<String> {
1343                 if self.is_primitive(full_path) {
1344                         return Some("".to_owned());
1345                 }
1346                 match full_path {
1347                         "Result" if !is_ref => Some("local_"),
1348                         "Vec" if !is_ref => Some("local_"),
1349                         "Option" => Some("local_"),
1350
1351                         "[u8; 32]" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1352                         "[u8; 32]" if is_ref => Some(""),
1353                         "[u8; 20]" if !is_ref => Some("crate::c_types::TwentyBytes { data: "),
1354                         "[u8; 16]" if !is_ref => Some("crate::c_types::SixteenBytes { data: "),
1355                         "[u8; 12]" if !is_ref => Some("crate::c_types::TwelveBytes { data: "),
1356                         "[u8; 4]" if !is_ref => Some("crate::c_types::FourBytes { data: "),
1357                         "[u8; 3]" if is_ref => Some(""),
1358                         "[u16; 8]" if !is_ref => Some("crate::c_types::EightU16s { data: "),
1359
1360                         "[u8]" if is_ref => Some("local_"),
1361                         "[usize]" if is_ref => Some("local_"),
1362
1363                         "str" if is_ref => Some(""),
1364                         "alloc::string::String"|"String" => Some(""),
1365
1366                         "bitcoin::Address" => Some("alloc::string::ToString::to_string(&"),
1367
1368                         "std::time::Duration"|"core::time::Duration" => Some(""),
1369                         "std::time::SystemTime" => Some(""),
1370                         "std::io::Error"|"lightning::io::Error" => Some("crate::c_types::IOError::from_rust("),
1371                         "lightning::io::ErrorKind" => Some("crate::c_types::IOError::from_rust_kind("),
1372                         "core::fmt::Arguments" => Some("alloc::format!(\"{}\", "),
1373
1374                         "core::convert::Infallible" => Some("panic!(\"Cannot construct an Infallible: "),
1375
1376                         "bitcoin::bech32::Error"|"bech32::Error"
1377                                 if !is_ref => Some("crate::c_types::Bech32Error::from_rust("),
1378                         "bitcoin::secp256k1::Error"|"secp256k1::Error"
1379                                 if !is_ref => Some("crate::c_types::Secp256k1Error::from_rust("),
1380
1381                         "core::num::ParseIntError" => Some("crate::c_types::Error { _dummy: 0 } /*"),
1382                         "core::str::Utf8Error" => Some("crate::c_types::Error { _dummy: 0 } /*"),
1383
1384                         "bitcoin::bech32::u5"|"bech32::u5" => Some(""),
1385                         "u128" => Some(""),
1386
1387                         "bitcoin::secp256k1::PublicKey"|"secp256k1::PublicKey" => Some("crate::c_types::PublicKey::from_rust(&"),
1388                         "bitcoin::secp256k1::ecdsa::Signature" => Some("crate::c_types::Signature::from_rust(&"),
1389                         "bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some("crate::c_types::RecoverableSignature::from_rust(&"),
1390                         "bitcoin::secp256k1::SecretKey" if is_ref => Some(""),
1391                         "bitcoin::secp256k1::SecretKey" if !is_ref => Some("crate::c_types::SecretKey::from_rust("),
1392                         "bitcoin::secp256k1::KeyPair" if !is_ref => Some("crate::c_types::SecretKey::from_rust("),
1393                         "bitcoin::secp256k1::Scalar" if !is_ref => Some("crate::c_types::BigEndianScalar::from_rust(&"),
1394                         "bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1395
1396                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if is_ref => Some("crate::c_types::u8slice::from_slice(&"),
1397                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if !is_ref => Some(""),
1398                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" if is_ref => Some("crate::c_types::Transaction::from_bitcoin("),
1399                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" => Some("crate::c_types::Transaction::from_bitcoin(&"),
1400                         "bitcoin::Witness" if is_ref => Some("crate::c_types::Witness::from_bitcoin("),
1401                         "bitcoin::Witness" if !is_ref => Some("crate::c_types::Witness::from_bitcoin(&"),
1402                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" if is_ref => Some("crate::c_types::bitcoin_to_C_outpoint("),
1403                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" if !is_ref => Some("crate::c_types::bitcoin_to_C_outpoint(&"),
1404                         "bitcoin::TxIn"|"bitcoin::blockdata::transaction::TxIn" if !is_ref => Some("crate::c_types::TxIn::from_rust(&"),
1405                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" if !is_ref => Some("crate::c_types::TxOut::from_rust(&"),
1406                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" if is_ref => Some("crate::c_types::TxOut::from_rust("),
1407                         "bitcoin::network::constants::Network" => Some("crate::bitcoin::network::Network::from_bitcoin("),
1408                         "bitcoin::util::address::WitnessVersion" => Some(""),
1409                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some("&local_"),
1410                         "bitcoin::blockdata::block::Block" if is_ref => Some("crate::c_types::u8slice::from_slice(&local_"),
1411
1412                         "bitcoin::PackedLockTime"|"bitcoin::blockdata::locktime::PackedLockTime" => Some(""),
1413
1414                         "bitcoin::psbt::PartiallySignedTransaction" if !is_ref => Some("::bitcoin::consensus::encode::serialize(&"),
1415
1416                         "bitcoin::hash_types::Txid" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1417
1418                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1419                         "bitcoin::hash_types::WPubkeyHash"|"bitcoin::hash_types::WScriptHash"|
1420                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1421                                 if !is_ref => Some("crate::c_types::TwentyBytes { data: "),
1422
1423                         // Newtypes that we just expose in their original form.
1424                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"|"bitcoin::blockdata::constants::ChainHash"
1425                                 if is_ref => Some(""),
1426                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"|"bitcoin::blockdata::constants::ChainHash"
1427                                 if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1428                         "bitcoin::secp256k1::Message" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1429                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1430                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1431                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1432                                 if is_ref => Some("&"),
1433                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1434                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1435                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1436                                 if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1437
1438                         "lightning::io::Read" => Some("crate::c_types::u8slice::from_vec(&crate::c_types::reader_to_vec("),
1439
1440                         _ => None,
1441                 }.map(|s| s.to_owned())
1442         }
1443         fn to_c_conversion_inline_suffix_from_path(&self, full_path: &str, is_ref: bool, _ptr_for_ref: bool) -> Option<String> {
1444                 if self.is_primitive(full_path) {
1445                         return Some("".to_owned());
1446                 }
1447                 match full_path {
1448                         "Result" if !is_ref => Some(""),
1449                         "Vec" if !is_ref => Some(".into()"),
1450                         "Option" => Some(""),
1451
1452                         "[u8; 32]" if !is_ref => Some(" }"),
1453                         "[u8; 32]" if is_ref => Some(""),
1454                         "[u8; 20]" if !is_ref => Some(" }"),
1455                         "[u8; 16]" if !is_ref => Some(" }"),
1456                         "[u8; 12]" if !is_ref => Some(" }"),
1457                         "[u8; 4]" if !is_ref => Some(" }"),
1458                         "[u8; 3]" if is_ref => Some(""),
1459                         "[u16; 8]" if !is_ref => Some(" }"),
1460
1461                         "[u8]" if is_ref => Some(""),
1462                         "[usize]" if is_ref => Some(""),
1463
1464                         "str" if is_ref => Some(".into()"),
1465                         "alloc::string::String"|"String" if is_ref => Some(".as_str().into()"),
1466                         "alloc::string::String"|"String" => Some(".into()"),
1467
1468                         "bitcoin::Address" => Some(").into()"),
1469
1470                         "std::time::Duration"|"core::time::Duration" => Some(".as_secs()"),
1471                         "std::time::SystemTime" => Some(".duration_since(::std::time::SystemTime::UNIX_EPOCH).expect(\"Times must be post-1970\").as_secs()"),
1472                         "std::io::Error"|"lightning::io::Error"|"lightning::io::ErrorKind" => Some(")"),
1473                         "core::fmt::Arguments" => Some(").into()"),
1474
1475                         "core::convert::Infallible" => Some("\")"),
1476
1477                         "bitcoin::secp256k1::Error"|"bech32::Error"
1478                                 if !is_ref => Some(")"),
1479                         "bitcoin::secp256k1::Error"|"secp256k1::Error"
1480                                 if !is_ref => Some(")"),
1481
1482                         "core::num::ParseIntError" => Some("*/"),
1483                         "core::str::Utf8Error" => Some("*/"),
1484
1485                         "bitcoin::bech32::u5"|"bech32::u5" => Some(".into()"),
1486                         "u128" => Some(".into()"),
1487
1488                         "bitcoin::secp256k1::PublicKey"|"secp256k1::PublicKey" => Some(")"),
1489                         "bitcoin::secp256k1::ecdsa::Signature" => Some(")"),
1490                         "bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some(")"),
1491                         "bitcoin::secp256k1::SecretKey" if !is_ref => Some(")"),
1492                         "bitcoin::secp256k1::SecretKey" if is_ref => Some(".as_ref()"),
1493                         "bitcoin::secp256k1::KeyPair" if !is_ref => Some(".secret_key())"),
1494                         "bitcoin::secp256k1::Scalar" if !is_ref => Some(")"),
1495                         "bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some(".secret_bytes() }"),
1496
1497                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if is_ref => Some("[..])"),
1498                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if !is_ref => Some(".into_bytes().into()"),
1499                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" => Some(")"),
1500                         "bitcoin::Witness" => Some(")"),
1501                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" => Some(")"),
1502                         "bitcoin::TxIn"|"bitcoin::blockdata::transaction::TxIn" if !is_ref => Some(")"),
1503                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" => Some(")"),
1504                         "bitcoin::network::constants::Network" => Some(")"),
1505                         "bitcoin::util::address::WitnessVersion" => Some(".into()"),
1506                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some(""),
1507                         "bitcoin::blockdata::block::Block" if is_ref => Some(")"),
1508
1509                         "bitcoin::PackedLockTime"|"bitcoin::blockdata::locktime::PackedLockTime" => Some(".0"),
1510
1511                         "bitcoin::psbt::PartiallySignedTransaction" if !is_ref => Some(").into()"),
1512
1513                         "bitcoin::hash_types::Txid" if !is_ref => Some(".into_inner() }"),
1514
1515                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1516                         "bitcoin::hash_types::WPubkeyHash"|"bitcoin::hash_types::WScriptHash"|
1517                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1518                                 if !is_ref => Some(".as_hash().into_inner() }"),
1519
1520                         // Newtypes that we just expose in their original form.
1521                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"
1522                                 if is_ref => Some(".as_inner()"),
1523                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"
1524                                 if !is_ref => Some(".into_inner() }"),
1525                         "bitcoin::blockdata::constants::ChainHash" if is_ref => Some(".as_bytes() }"),
1526                         "bitcoin::blockdata::constants::ChainHash" if !is_ref => Some(".to_bytes() }"),
1527                         "bitcoin::secp256k1::Message" if !is_ref => Some(".as_ref().clone() }"),
1528                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1529                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1530                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1531                                 if is_ref => Some(".0"),
1532                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1533                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1534                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1535                                 if !is_ref => Some(".0 }"),
1536
1537                         "lightning::io::Read" => Some("))"),
1538
1539                         _ => None,
1540                 }.map(|s| s.to_owned())
1541         }
1542
1543         fn empty_val_check_suffix_from_path(&self, full_path: &str) -> Option<&str> {
1544                 match full_path {
1545                         "secp256k1::PublicKey"|"bitcoin::secp256k1::PublicKey" => Some(".is_null()"),
1546                         _ => None
1547                 }
1548         }
1549
1550         /// When printing a reference to the source crate's rust type, if we need to map it to a
1551         /// different "real" type, it can be done so here.
1552         /// This is useful to work around limitations in the binding type resolver, where we reference
1553         /// a non-public `use` alias.
1554         /// TODO: We should never need to use this!
1555         fn real_rust_type_mapping<'equiv>(&self, thing: &'equiv str) -> &'equiv str {
1556                 match thing {
1557                         "lightning::io::Read" => "crate::c_types::io::Read",
1558                         _ => thing,
1559                 }
1560         }
1561
1562         // ****************************
1563         // *** Container Processing ***
1564         // ****************************
1565
1566         /// Returns the module path in the generated mapping crate to the containers which we generate
1567         /// when writing to CrateTypes::template_file.
1568         pub fn generated_container_path() -> &'static str {
1569                 "crate::c_types::derived"
1570         }
1571         /// Returns the module path in the generated mapping crate to the container templates, which
1572         /// are then concretized and put in the generated container path/template_file.
1573         fn container_templ_path() -> &'static str {
1574                 "crate::c_types"
1575         }
1576
1577         /// This should just be a closure, but doing so gets an error like
1578         /// error: reached the recursion limit while instantiating `types::TypeResolver::is_transpar...c/types.rs:1358:104: 1358:110]>>`
1579         /// which implies the concrete function instantiation of `is_transparent_container` ends up
1580         /// being recursive.
1581         fn deref_type<'one, 'b: 'one> (obj: &'one &'b syn::Type) -> &'b syn::Type { *obj }
1582
1583         /// Returns true if the path containing the given args is a "transparent" container, ie an
1584         /// Option or a container which does not require a generated continer class.
1585         fn is_transparent_container<'i, I: Iterator<Item=&'i syn::Type>>(&self, full_path: &str, _is_ref: bool, mut args: I, generics: Option<&GenericTypes>) -> bool {
1586                 if full_path == "Option" {
1587                         let inner = args.next().unwrap();
1588                         assert!(args.next().is_none());
1589                         match generics.resolve_type(inner) {
1590                                 syn::Type::Reference(r) => {
1591                                         let elem = &*r.elem;
1592                                         match elem {
1593                                                 syn::Type::Path(_) =>
1594                                                         self.is_transparent_container(full_path, true, [elem].iter().map(Self::deref_type), generics),
1595                                                 _ => true,
1596                                         }
1597                                 },
1598                                 syn::Type::Array(a) => {
1599                                         if let syn::Expr::Lit(l) = &a.len {
1600                                                 if let syn::Lit::Int(i) = &l.lit {
1601                                                         if i.base10_digits().parse::<usize>().unwrap() >= 32 {
1602                                                                 let mut buf = Vec::new();
1603                                                                 self.write_rust_type(&mut buf, generics, &a.elem, false);
1604                                                                 let ty = String::from_utf8(buf).unwrap();
1605                                                                 ty == "u8"
1606                                                         } else {
1607                                                                 // Blindly assume that if we're trying to create an empty value for an
1608                                                                 // array < 32 entries that all-0s may be a valid state.
1609                                                                 unimplemented!();
1610                                                         }
1611                                                 } else { unimplemented!(); }
1612                                         } else { unimplemented!(); }
1613                                 },
1614                                 syn::Type::Path(p) => {
1615                                         if let Some(resolved) = self.maybe_resolve_path(&p.path, generics) {
1616                                                 if self.c_type_has_inner_from_path(&resolved) { return true; }
1617                                                 if self.is_primitive(&resolved) { return false; }
1618                                                 // We want to move to using `Option_` mappings where possible rather than
1619                                                 // manual mappings, as it makes downstream bindings simpler and is more
1620                                                 // clear for users. Thus, we default to false but override for a few
1621                                                 // types which had mappings defined when we were avoiding the `Option_`s.
1622                                                 match &resolved as &str {
1623                                                         "secp256k1::PublicKey"|"bitcoin::secp256k1::PublicKey" => true,
1624                                                         _ => false,
1625                                                 }
1626                                         } else { unimplemented!(); }
1627                                 },
1628                                 syn::Type::Tuple(_) => false,
1629                                 _ => unimplemented!(),
1630                         }
1631                 } else { false }
1632         }
1633         /// Returns true if the path is a "transparent" container, ie an Option or a container which does
1634         /// not require a generated continer class.
1635         pub fn is_path_transparent_container(&self, full_path: &syn::Path, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
1636                 let inner_iter = match &full_path.segments.last().unwrap().arguments {
1637                         syn::PathArguments::None => return false,
1638                         syn::PathArguments::AngleBracketed(args) => args.args.iter().map(|arg| {
1639                                 if let syn::GenericArgument::Type(ref ty) = arg {
1640                                         ty
1641                                 } else { unimplemented!() }
1642                         }),
1643                         syn::PathArguments::Parenthesized(_) => unimplemented!(),
1644                 };
1645                 self.is_transparent_container(&self.resolve_path(full_path, generics), is_ref, inner_iter, generics)
1646         }
1647         /// Returns true if this is a known, supported, non-transparent container.
1648         fn is_known_container(&self, full_path: &str, is_ref: bool) -> bool {
1649                 (full_path == "Result" && !is_ref) || (full_path == "Vec" && !is_ref) || full_path.ends_with("Tuple") || full_path == "Option"
1650         }
1651         fn to_c_conversion_container_new_var<'b>(&self, generics: Option<&GenericTypes>, full_path: &str, is_ref: bool, single_contained: Option<&syn::Type>, var_name: &syn::Ident, var_access: &str)
1652                         // Returns prefix + Vec<(prefix, var-name-to-inline-convert)> + suffix
1653                         // expecting one element in the vec per generic type, each of which is inline-converted
1654                         -> Option<(&'b str, Vec<(String, String)>, &'b str, ContainerPrefixLocation)> {
1655                 match full_path {
1656                         "Result" if !is_ref => {
1657                                 Some(("match ",
1658                                                 vec![(" { Ok(mut o) => crate::c_types::CResultTempl::ok(".to_string(), "o".to_string()),
1659                                                         (").into(), Err(mut e) => crate::c_types::CResultTempl::err(".to_string(), "e".to_string())],
1660                                                 ").into() }", ContainerPrefixLocation::PerConv))
1661                         },
1662                         "Vec" => {
1663                                 if is_ref {
1664                                         // We should only get here if the single contained has an inner
1665                                         assert!(self.c_type_has_inner(single_contained.unwrap()));
1666                                 }
1667                                 Some(("Vec::new(); for mut item in ", vec![(format!(".drain(..) {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1668                         },
1669                         "Slice" => {
1670                                 if let Some(syn::Type::Reference(_)) = single_contained {
1671                                         Some(("Vec::new(); for item in ", vec![(format!(".iter() {{ local_{}.push(", var_name), "(*item)".to_string())], "); }", ContainerPrefixLocation::PerConv))
1672                                 } else {
1673                                         Some(("Vec::new(); for item in ", vec![(format!(".iter() {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1674                                 }
1675                         },
1676                         "Option" => {
1677                                 let mut is_contained_ref = false;
1678                                 let contained_struct = if let Some(syn::Type::Path(p)) = single_contained {
1679                                         Some(self.resolve_path(&p.path, generics))
1680                                 } else if let Some(syn::Type::Reference(r)) = single_contained {
1681                                         is_contained_ref = true;
1682                                         if let syn::Type::Path(p) = &*r.elem {
1683                                                 Some(self.resolve_path(&p.path, generics))
1684                                         } else { None }
1685                                 } else { None };
1686                                 if let Some(inner_path) = contained_struct {
1687                                         let only_contained_has_inner = self.c_type_has_inner_from_path(&inner_path);
1688                                         if self.c_type_has_inner_from_path(&inner_path) {
1689                                                 let is_inner_ref = if let Some(syn::Type::Reference(_)) = single_contained { true } else { false };
1690                                                 if is_ref {
1691                                                         return Some(("if ", vec![
1692                                                                 (".is_none() { core::ptr::null() } else { ObjOps::nonnull_ptr_to_inner(".to_owned(),
1693                                                                         format!("({}{}.unwrap())", var_access, if is_inner_ref { "" } else { ".as_ref()" }))
1694                                                                 ], ") }", ContainerPrefixLocation::OutsideConv));
1695                                                 } else {
1696                                                         return Some(("if ", vec![
1697                                                                 (".is_none() { core::ptr::null_mut() } else { ".to_owned(), format!("({}.unwrap())", var_access))
1698                                                                 ], " }", ContainerPrefixLocation::OutsideConv));
1699                                                 }
1700                                         } else if !self.is_transparent_container("Option", is_ref, [single_contained.unwrap()].iter().map(|a| *a), generics) {
1701                                                 if self.is_primitive(&inner_path) || (!is_contained_ref && !is_ref) || only_contained_has_inner {
1702                                                         let inner_name = self.get_c_mangled_container_type(vec![single_contained.unwrap()], generics, "Option").unwrap();
1703                                                         return Some(("if ", vec![
1704                                                                 (format!(".is_none() {{ {}::None }} else {{ {}::Some(", inner_name, inner_name),
1705                                                                  format!("{}.unwrap()", var_access))
1706                                                                 ], ") }", ContainerPrefixLocation::PerConv));
1707                                                 } else {
1708                                                         let inner_name = self.get_c_mangled_container_type(vec![single_contained.unwrap()], generics, "Option").unwrap();
1709                                                         return Some(("if ", vec![
1710                                                                 (format!(".is_none() {{ {}::None }} else {{ {}::Some(/* WARNING: CLONING CONVERSION HERE! &Option<Enum> is otherwise un-expressable. */", inner_name, inner_name),
1711                                                                  format!("(*{}.as_ref().unwrap()).clone()", var_access))
1712                                                                 ], ") }", ContainerPrefixLocation::PerConv));
1713                                                 }
1714                                         } else {
1715                                                 // If c_type_from_path is some (ie there's a manual mapping for the inner
1716                                                 // type), lean on write_empty_rust_val, below.
1717                                         }
1718                                 }
1719                                 if let Some(t) = single_contained {
1720                                         if let syn::Type::Tuple(syn::TypeTuple { elems, .. }) = t {
1721                                                 let inner_name = self.get_c_mangled_container_type(vec![single_contained.unwrap()], generics, "Option").unwrap();
1722                                                 if elems.is_empty() {
1723                                                         return Some(("if ", vec![
1724                                                                 (format!(".is_none() {{ {}::None }} else {{ {}::Some /* ",
1725                                                                         inner_name, inner_name), format!(""))
1726                                                                 ], " */ }", ContainerPrefixLocation::PerConv));
1727                                                 } else {
1728                                                         return Some(("if ", vec![
1729                                                                 (format!(".is_none() {{ {}::None }} else {{ {}::Some(",
1730                                                                         inner_name, inner_name), format!("({}.unwrap())", var_access))
1731                                                                 ], ") }", ContainerPrefixLocation::PerConv));
1732                                                 }
1733                                         }
1734                                         if let syn::Type::Reference(syn::TypeReference { elem, .. }) = t {
1735                                                 if let syn::Type::Slice(_) = &**elem {
1736                                                         return Some(("if ", vec![
1737                                                                         (".is_none() { SmartPtr::null() } else { SmartPtr::from_obj(".to_string(),
1738                                                                          format!("({}.unwrap())", var_access))
1739                                                                 ], ") }", ContainerPrefixLocation::PerConv));
1740                                                 }
1741                                         }
1742                                         let mut v = Vec::new();
1743                                         self.write_empty_rust_val(generics, &mut v, t);
1744                                         let s = String::from_utf8(v).unwrap();
1745                                         return Some(("if ", vec![
1746                                                 (format!(".is_none() {{ {} }} else {{ ", s), format!("({}.unwrap())", var_access))
1747                                                 ], " }", ContainerPrefixLocation::PerConv));
1748                                 } else { unreachable!(); }
1749                         },
1750                         _ => None,
1751                 }
1752         }
1753
1754         /// only_contained_has_inner implies that there is only one contained element in the container
1755         /// and it has an inner field (ie is an "opaque" type we've defined).
1756         fn from_c_conversion_container_new_var<'b>(&self, generics: Option<&GenericTypes>, full_path: &str, is_ref: bool, single_contained: Option<&syn::Type>, var_name: &syn::Ident, var_access: &str)
1757                         // Returns prefix + Vec<(prefix, var-name-to-inline-convert)> + suffix
1758                         // expecting one element in the vec per generic type, each of which is inline-converted
1759                         -> Option<(&'b str, Vec<(String, String)>, &'b str, ContainerPrefixLocation)> {
1760                 let mut only_contained_has_inner = false;
1761                 let only_contained_resolved = if let Some(syn::Type::Path(p)) = single_contained {
1762                         let res = self.resolve_path(&p.path, generics);
1763                         only_contained_has_inner = self.c_type_has_inner_from_path(&res);
1764                         Some(res)
1765                 } else { None };
1766                 match full_path {
1767                         "Result" if !is_ref => {
1768                                 Some(("match ",
1769                                                 vec![(".result_ok { true => Ok(".to_string(), format!("(*unsafe {{ Box::from_raw(<*mut _>::take_ptr(&mut {}.contents.result)) }})", var_access)),
1770                                                      ("), false => Err(".to_string(), format!("(*unsafe {{ Box::from_raw(<*mut _>::take_ptr(&mut {}.contents.err)) }})", var_access))],
1771                                                 ")}", ContainerPrefixLocation::PerConv))
1772                         },
1773                         "Slice" if is_ref && only_contained_has_inner => {
1774                                 Some(("Vec::new(); for mut item in ", vec![(format!(".as_slice().iter() {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1775                         },
1776                         "Vec"|"Slice" => {
1777                                 Some(("Vec::new(); for mut item in ", vec![(format!(".into_rust().drain(..) {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1778                         },
1779                         "Option" => {
1780                                 if let Some(resolved) = only_contained_resolved {
1781                                         if self.is_primitive(&resolved) {
1782                                                 return Some(("if ", vec![(".is_some() { Some(".to_string(), format!("{}.take()", var_access))], ") } else { None }", ContainerPrefixLocation::NoPrefix))
1783                                         } else if only_contained_has_inner {
1784                                                 if is_ref {
1785                                                         return Some(("if ", vec![(".inner.is_null() { None } else { Some((*".to_string(), format!("{}", var_access))], ").clone()) }", ContainerPrefixLocation::PerConv))
1786                                                 } else {
1787                                                         return Some(("if ", vec![(".inner.is_null() { None } else { Some(".to_string(), format!("{}", var_access))], ") }", ContainerPrefixLocation::PerConv));
1788                                                 }
1789                                         }
1790                                 }
1791
1792                                 if let Some(t) = single_contained {
1793                                         match t {
1794                                                 syn::Type::Reference(_)|syn::Type::Path(_)|syn::Type::Slice(_)|syn::Type::Array(_) => {
1795                                                         let mut v = Vec::new();
1796                                                         let ret_ref = self.write_empty_rust_val_check_suffix(generics, &mut v, t);
1797                                                         let s = String::from_utf8(v).unwrap();
1798                                                         match ret_ref {
1799                                                                 EmptyValExpectedTy::ReferenceAsPointer =>
1800                                                                         return Some(("if ", vec![
1801                                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("unsafe {{ &mut *{} }}", var_access))
1802                                                                         ], ") }", ContainerPrefixLocation::NoPrefix)),
1803                                                                 EmptyValExpectedTy::OptionType =>
1804                                                                         return Some(("{ /*", vec![
1805                                                                                 (format!("*/ let {}_opt = {}; if {}_opt{} {{ None }} else {{ Some({{", var_name, var_access, var_name, s),
1806                                                                                 format!("{{ {}_opt.take() }}", var_name))
1807                                                                         ], "})} }", ContainerPrefixLocation::PerConv)),
1808                                                                 EmptyValExpectedTy::NonPointer =>
1809                                                                         return Some(("if ", vec![
1810                                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("{}", var_access))
1811                                                                         ], ") }", ContainerPrefixLocation::PerConv)),
1812                                                         }
1813                                                 },
1814                                                 syn::Type::Tuple(_) => {
1815                                                         return Some(("if ", vec![(".is_some() { Some(".to_string(), format!("{}.take()", var_access))], ") } else { None }", ContainerPrefixLocation::PerConv))
1816                                                 },
1817                                                 _ => unimplemented!(),
1818                                         }
1819                                 } else { unreachable!(); }
1820                         },
1821                         _ => None,
1822                 }
1823         }
1824
1825         /// Constructs a reference to the given type, possibly tweaking the type if relevant to make it
1826         /// convertable to C.
1827         pub fn create_ownable_reference(&self, t: &syn::Type, generics: Option<&GenericTypes>) -> Option<syn::Type> {
1828                 let default_value = Some(syn::Type::Reference(syn::TypeReference {
1829                         and_token: syn::Token!(&)(Span::call_site()), lifetime: None, mutability: None,
1830                         elem: Box::new(t.clone()) }));
1831                 match generics.resolve_type(t) {
1832                         syn::Type::Path(p) => {
1833                                 if let Some(resolved_path) = self.maybe_resolve_path(&p.path, generics) {
1834                                         if resolved_path != "Vec" { return default_value; }
1835                                         if p.path.segments.len() != 1 { unimplemented!(); }
1836                                         let only_seg = p.path.segments.iter().next().unwrap();
1837                                         if let syn::PathArguments::AngleBracketed(args) = &only_seg.arguments {
1838                                                 if args.args.len() != 1 { unimplemented!(); }
1839                                                 let inner_arg = args.args.iter().next().unwrap();
1840                                                 if let syn::GenericArgument::Type(ty) = &inner_arg {
1841                                                         let mut can_create = self.c_type_has_inner(&ty);
1842                                                         if let syn::Type::Path(inner) = ty {
1843                                                                 if inner.path.segments.len() == 1 &&
1844                                                                                 format!("{}", inner.path.segments[0].ident) == "Vec" {
1845                                                                         can_create = true;
1846                                                                 }
1847                                                         }
1848                                                         if !can_create { return default_value; }
1849                                                         if let Some(inner_ty) = self.create_ownable_reference(&ty, generics) {
1850                                                                 return Some(syn::Type::Reference(syn::TypeReference {
1851                                                                         and_token: syn::Token![&](Span::call_site()),
1852                                                                         lifetime: None,
1853                                                                         mutability: None,
1854                                                                         elem: Box::new(syn::Type::Slice(syn::TypeSlice {
1855                                                                                 bracket_token: syn::token::Bracket { span: Span::call_site() },
1856                                                                                 elem: Box::new(inner_ty)
1857                                                                         }))
1858                                                                 }));
1859                                                         } else { return default_value; }
1860                                                 } else { unimplemented!(); }
1861                                         } else { unimplemented!(); }
1862                                 } else { return None; }
1863                         },
1864                         _ => default_value,
1865                 }
1866         }
1867
1868         // *************************************************
1869         // *** Type definition during main.rs processing ***
1870         // *************************************************
1871
1872         /// Returns true if the object at the given path is mapped as X { inner: *mut origX, .. }.
1873         pub fn c_type_has_inner_from_path(&self, full_path: &str) -> bool {
1874                 self.crate_types.opaques.get(full_path).is_some()
1875         }
1876
1877         /// Returns true if the object at the given path is mapped as X { inner: *mut origX, .. }.
1878         pub fn c_type_has_inner(&self, ty: &syn::Type) -> bool {
1879                 match ty {
1880                         syn::Type::Path(p) => {
1881                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, None) {
1882                                         self.c_type_has_inner_from_path(&full_path)
1883                                 } else { false }
1884                         },
1885                         syn::Type::Reference(r) => {
1886                                 self.c_type_has_inner(&*r.elem)
1887                         },
1888                         _ => false,
1889                 }
1890         }
1891
1892         pub fn maybe_resolve_ident(&self, id: &syn::Ident) -> Option<String> {
1893                 self.types.maybe_resolve_ident(id)
1894         }
1895
1896         pub fn maybe_resolve_path(&self, p_arg: &syn::Path, generics: Option<&GenericTypes>) -> Option<String> {
1897                 self.types.maybe_resolve_path(p_arg, generics)
1898         }
1899         pub fn resolve_path(&self, p: &syn::Path, generics: Option<&GenericTypes>) -> String {
1900                 self.maybe_resolve_path(p, generics).unwrap()
1901         }
1902
1903         // ***********************************
1904         // *** Original Rust Type Printing ***
1905         // ***********************************
1906
1907         fn in_rust_prelude(resolved_path: &str) -> bool {
1908                 match resolved_path {
1909                         "Vec" => true,
1910                         "Result" => true,
1911                         "Option" => true,
1912                         _ => false,
1913                 }
1914         }
1915
1916         fn write_rust_path<W: std::io::Write>(&self, w: &mut W, generics_resolver: Option<&GenericTypes>, path: &syn::Path, with_ref_lifetime: bool, generated_crate_ref: bool) {
1917                 if let Some(resolved) = self.maybe_resolve_path(&path, generics_resolver) {
1918                         if self.is_primitive(&resolved) {
1919                                 write!(w, "{}", path.get_ident().unwrap()).unwrap();
1920                         } else {
1921                                 // TODO: We should have a generic "is from a dependency" check here instead of
1922                                 // checking for "bitcoin" explicitly.
1923                                 if resolved.starts_with("bitcoin::") || Self::in_rust_prelude(&resolved) {
1924                                         write!(w, "{}", resolved).unwrap();
1925                                 } else if !generated_crate_ref {
1926                                         // If we're printing a generic argument, it needs to reference the crate, otherwise
1927                                         // the original crate.
1928                                         write!(w, "{}", self.real_rust_type_mapping(&resolved)).unwrap();
1929                                 } else {
1930                                         write!(w, "crate::{}", resolved).unwrap();
1931                                 }
1932                         }
1933                         if let syn::PathArguments::AngleBracketed(args) = &path.segments.iter().last().unwrap().arguments {
1934                                 self.write_rust_generic_arg(w, generics_resolver, args.args.iter(), with_ref_lifetime);
1935                         }
1936                 } else {
1937                         if path.leading_colon.is_some() {
1938                                 write!(w, "::").unwrap();
1939                         }
1940                         for (idx, seg) in path.segments.iter().enumerate() {
1941                                 if idx != 0 { write!(w, "::").unwrap(); }
1942                                 write!(w, "{}", seg.ident).unwrap();
1943                                 if let syn::PathArguments::AngleBracketed(args) = &seg.arguments {
1944                                         self.write_rust_generic_arg(w, generics_resolver, args.args.iter(), with_ref_lifetime);
1945                                 }
1946                         }
1947                 }
1948         }
1949         pub fn write_rust_generic_param<'b, W: std::io::Write>(&self, w: &mut W, generics_resolver: Option<&GenericTypes>, generics: impl Iterator<Item=&'b syn::GenericParam>) {
1950                 let mut had_params = false;
1951                 for (idx, arg) in generics.enumerate() {
1952                         if idx != 0 { write!(w, ", ").unwrap(); } else { write!(w, "<").unwrap(); }
1953                         had_params = true;
1954                         match arg {
1955                                 syn::GenericParam::Lifetime(lt) => write!(w, "'{}", lt.lifetime.ident).unwrap(),
1956                                 syn::GenericParam::Type(t) => {
1957                                         write!(w, "{}", t.ident).unwrap();
1958                                         if t.colon_token.is_some() { write!(w, ":").unwrap(); }
1959                                         for (idx, bound) in t.bounds.iter().enumerate() {
1960                                                 if idx != 0 { write!(w, " + ").unwrap(); }
1961                                                 match bound {
1962                                                         syn::TypeParamBound::Trait(tb) => {
1963                                                                 if tb.paren_token.is_some() || tb.lifetimes.is_some() { unimplemented!(); }
1964                                                                 self.write_rust_path(w, generics_resolver, &tb.path, false, false);
1965                                                         },
1966                                                         _ => unimplemented!(),
1967                                                 }
1968                                         }
1969                                         if t.eq_token.is_some() || t.default.is_some() { unimplemented!(); }
1970                                 },
1971                                 _ => unimplemented!(),
1972                         }
1973                 }
1974                 if had_params { write!(w, ">").unwrap(); }
1975         }
1976
1977         pub fn write_rust_generic_arg<'b, W: std::io::Write>(&self, w: &mut W, generics_resolver: Option<&GenericTypes>, generics: impl Iterator<Item=&'b syn::GenericArgument>, with_ref_lifetime: bool) {
1978                 write!(w, "<").unwrap();
1979                 for (idx, arg) in generics.enumerate() {
1980                         if idx != 0 { write!(w, ", ").unwrap(); }
1981                         match arg {
1982                                 syn::GenericArgument::Type(t) => self.write_rust_type(w, generics_resolver, t, with_ref_lifetime),
1983                                 _ => unimplemented!(),
1984                         }
1985                 }
1986                 write!(w, ">").unwrap();
1987         }
1988         fn do_write_rust_type<W: std::io::Write>(&self, w: &mut W, generics: Option<&GenericTypes>, t: &syn::Type, with_ref_lifetime: bool, force_crate_ref: bool) {
1989                 let real_ty = generics.resolve_type(t);
1990                 let mut generate_crate_ref = force_crate_ref || t != real_ty;
1991                 match real_ty {
1992                         syn::Type::Path(p) => {
1993                                 if p.qself.is_some() {
1994                                         unimplemented!();
1995                                 }
1996                                 if let Some(resolved_ty) = self.maybe_resolve_path(&p.path, generics) {
1997                                         generate_crate_ref |= self.maybe_resolve_path(&p.path, None).as_ref() != Some(&resolved_ty);
1998                                         if self.crate_types.traits.get(&resolved_ty).is_none() { generate_crate_ref = false; }
1999                                 }
2000                                 self.write_rust_path(w, generics, &p.path, with_ref_lifetime, generate_crate_ref);
2001                         },
2002                         syn::Type::Reference(r) => {
2003                                 write!(w, "&").unwrap();
2004                                 if let Some(lft) = &r.lifetime {
2005                                         write!(w, "'{} ", lft.ident).unwrap();
2006                                 } else if with_ref_lifetime {
2007                                         write!(w, "'static ").unwrap();
2008                                 }
2009                                 if r.mutability.is_some() {
2010                                         write!(w, "mut ").unwrap();
2011                                 }
2012                                 self.do_write_rust_type(w, generics, &*r.elem, with_ref_lifetime, generate_crate_ref);
2013                         },
2014                         syn::Type::Array(a) => {
2015                                 write!(w, "[").unwrap();
2016                                 self.do_write_rust_type(w, generics, &a.elem, with_ref_lifetime, generate_crate_ref);
2017                                 if let syn::Expr::Lit(l) = &a.len {
2018                                         if let syn::Lit::Int(i) = &l.lit {
2019                                                 write!(w, "; {}]", i).unwrap();
2020                                         } else { unimplemented!(); }
2021                                 } else { unimplemented!(); }
2022                         }
2023                         syn::Type::Slice(s) => {
2024                                 write!(w, "[").unwrap();
2025                                 self.do_write_rust_type(w, generics, &s.elem, with_ref_lifetime, generate_crate_ref);
2026                                 write!(w, "]").unwrap();
2027                         },
2028                         syn::Type::Tuple(s) => {
2029                                 write!(w, "(").unwrap();
2030                                 for (idx, t) in s.elems.iter().enumerate() {
2031                                         if idx != 0 { write!(w, ", ").unwrap(); }
2032                                         self.do_write_rust_type(w, generics, &t, with_ref_lifetime, generate_crate_ref);
2033                                 }
2034                                 write!(w, ")").unwrap();
2035                         },
2036                         _ => unimplemented!(),
2037                 }
2038         }
2039         pub fn write_rust_type<W: std::io::Write>(&self, w: &mut W, generics: Option<&GenericTypes>, t: &syn::Type, with_ref_lifetime: bool) {
2040                 self.do_write_rust_type(w, generics, t, with_ref_lifetime, false);
2041         }
2042
2043
2044         /// Prints a constructor for something which is "uninitialized" (but obviously not actually
2045         /// unint'd memory).
2046         pub fn write_empty_rust_val<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type) {
2047                 match t {
2048                         syn::Type::Reference(r) => {
2049                                 self.write_empty_rust_val(generics, w, &*r.elem)
2050                         },
2051                         syn::Type::Path(p) => {
2052                                 let resolved = self.resolve_path(&p.path, generics);
2053                                 if self.crate_types.opaques.get(&resolved).is_some() {
2054                                         write!(w, "crate::{} {{ inner: core::ptr::null_mut(), is_owned: true }}", resolved).unwrap();
2055                                 } else {
2056                                         // Assume its a manually-mapped C type, where we can just define an null() fn
2057                                         write!(w, "{}::null()", self.c_type_from_path(&resolved, false, false).unwrap()).unwrap();
2058                                 }
2059                         },
2060                         syn::Type::Array(a) => {
2061                                 if let syn::Expr::Lit(l) = &a.len {
2062                                         if let syn::Lit::Int(i) = &l.lit {
2063                                                 if i.base10_digits().parse::<usize>().unwrap() < 32 {
2064                                                         // Blindly assume that if we're trying to create an empty value for an
2065                                                         // array < 32 entries that all-0s may be a valid state.
2066                                                         unimplemented!();
2067                                                 }
2068                                                 let arrty = format!("[u8; {}]", i.base10_digits());
2069                                                 write!(w, "{}", self.to_c_conversion_inline_prefix_from_path(&arrty, false, false).unwrap()).unwrap();
2070                                                 write!(w, "[0; {}]", i.base10_digits()).unwrap();
2071                                                 write!(w, "{}", self.to_c_conversion_inline_suffix_from_path(&arrty, false, false).unwrap()).unwrap();
2072                                         } else { unimplemented!(); }
2073                                 } else { unimplemented!(); }
2074                         }
2075                         _ => unimplemented!(),
2076                 }
2077         }
2078
2079         /// Prints a suffix to determine if a variable is empty (ie was set by write_empty_rust_val).
2080         /// See EmptyValExpectedTy for information on return types.
2081         fn write_empty_rust_val_check_suffix<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type) -> EmptyValExpectedTy {
2082                 match t {
2083                         syn::Type::Reference(r) => {
2084                                 return self.write_empty_rust_val_check_suffix(generics, w, &*r.elem);
2085                         },
2086                         syn::Type::Path(p) => {
2087                                 let resolved = self.resolve_path(&p.path, generics);
2088                                 if self.crate_types.opaques.get(&resolved).is_some() {
2089                                         write!(w, ".inner.is_null()").unwrap();
2090                                         EmptyValExpectedTy::NonPointer
2091                                 } else {
2092                                         if let Some(suffix) = self.empty_val_check_suffix_from_path(&resolved) {
2093                                                 write!(w, "{}", suffix).unwrap();
2094                                                 // We may eventually need to allow empty_val_check_suffix_from_path to specify if we need a deref or not
2095                                                 EmptyValExpectedTy::NonPointer
2096                                         } else {
2097                                                 write!(w, ".is_none()").unwrap();
2098                                                 EmptyValExpectedTy::OptionType
2099                                         }
2100                                 }
2101                         },
2102                         syn::Type::Array(a) => {
2103                                 if let syn::Expr::Lit(l) = &a.len {
2104                                         if let syn::Lit::Int(i) = &l.lit {
2105                                                 write!(w, ".data == [0; {}]", i.base10_digits()).unwrap();
2106                                                 EmptyValExpectedTy::NonPointer
2107                                         } else { unimplemented!(); }
2108                                 } else { unimplemented!(); }
2109                         },
2110                         syn::Type::Slice(_) => {
2111                                 // Option<[]> always implies that we want to treat len() == 0 differently from
2112                                 // None, so we always map an Option<[]> into a pointer.
2113                                 write!(w, " == core::ptr::null_mut()").unwrap();
2114                                 EmptyValExpectedTy::ReferenceAsPointer
2115                         },
2116                         _ => unimplemented!(),
2117                 }
2118         }
2119
2120         /// Prints a suffix to determine if a variable is empty (ie was set by write_empty_rust_val).
2121         pub fn write_empty_rust_val_check<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type, var_access: &str) {
2122                 match t {
2123                         syn::Type::Reference(r) => {
2124                                 self.write_empty_rust_val_check(generics, w, &*r.elem, var_access);
2125                         },
2126                         syn::Type::Path(_) => {
2127                                 write!(w, "{}", var_access).unwrap();
2128                                 self.write_empty_rust_val_check_suffix(generics, w, t);
2129                         },
2130                         syn::Type::Array(a) => {
2131                                 if let syn::Expr::Lit(l) = &a.len {
2132                                         if let syn::Lit::Int(i) = &l.lit {
2133                                                 let arrty = format!("[u8; {}]", i.base10_digits());
2134                                                 // We don't (yet) support a new-var conversion here.
2135                                                 assert!(self.from_c_conversion_new_var_from_path(&arrty, false).is_none());
2136                                                 write!(w, "{}{}{}",
2137                                                         self.from_c_conversion_prefix_from_path(&arrty, false).unwrap(),
2138                                                         var_access,
2139                                                         self.from_c_conversion_suffix_from_path(&arrty, false).unwrap()).unwrap();
2140                                                 self.write_empty_rust_val_check_suffix(generics, w, t);
2141                                         } else { unimplemented!(); }
2142                                 } else { unimplemented!(); }
2143                         }
2144                         _ => unimplemented!(),
2145                 }
2146         }
2147
2148         // ********************************
2149         // *** Type conversion printing ***
2150         // ********************************
2151
2152         /// Returns true we if can just skip passing this to C entirely
2153         pub fn skip_arg(&self, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
2154                 match t {
2155                         syn::Type::Path(p) => {
2156                                 if p.qself.is_some() { unimplemented!(); }
2157                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
2158                                         self.skip_path(&full_path)
2159                                 } else { false }
2160                         },
2161                         syn::Type::Reference(r) => {
2162                                 self.skip_arg(&*r.elem, generics)
2163                         },
2164                         _ => false,
2165                 }
2166         }
2167         pub fn no_arg_to_rust<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
2168                 match t {
2169                         syn::Type::Path(p) => {
2170                                 if p.qself.is_some() { unimplemented!(); }
2171                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
2172                                         write!(w, "{}", self.no_arg_path_to_rust(&full_path)).unwrap();
2173                                 }
2174                         },
2175                         syn::Type::Reference(r) => {
2176                                 self.no_arg_to_rust(w, &*r.elem, generics);
2177                         },
2178                         _ => {},
2179                 }
2180         }
2181
2182         fn write_conversion_inline_intern<W: std::io::Write,
2183                         LP: Fn(&str, bool, bool) -> Option<String>, DL: Fn(&mut W, &DeclType, &str, bool, bool), SC: Fn(bool, Option<&str>) -> String>
2184                         (&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, is_mut: bool, ptr_for_ref: bool,
2185                          tupleconv: &str, prefix: bool, sliceconv: SC, path_lookup: LP, decl_lookup: DL) {
2186                 match generics.resolve_type(t) {
2187                         syn::Type::Reference(r) => {
2188                                 self.write_conversion_inline_intern(w, &*r.elem, generics, true, r.mutability.is_some(),
2189                                         ptr_for_ref, tupleconv, prefix, sliceconv, path_lookup, decl_lookup);
2190                         },
2191                         syn::Type::Path(p) => {
2192                                 if p.qself.is_some() {
2193                                         unimplemented!();
2194                                 }
2195
2196                                 let resolved_path = self.resolve_path(&p.path, generics);
2197                                 if let Some(aliased_type) = self.crate_types.type_aliases.get(&resolved_path) {
2198                                         return self.write_conversion_inline_intern(w, aliased_type, None, is_ref, is_mut, ptr_for_ref, tupleconv, prefix, sliceconv, path_lookup, decl_lookup);
2199                                 } else if self.is_primitive(&resolved_path) {
2200                                         if is_ref && prefix {
2201                                                 write!(w, "*").unwrap();
2202                                         }
2203                                 } else if let Some(c_type) = path_lookup(&resolved_path, is_ref, ptr_for_ref) {
2204                                         write!(w, "{}", c_type).unwrap();
2205                                 } else if let Some((_, generics)) = self.crate_types.opaques.get(&resolved_path) {
2206                                         decl_lookup(w, &DeclType::StructImported { generics: &generics }, &resolved_path, is_ref, is_mut);
2207                                 } else if self.crate_types.mirrored_enums.get(&resolved_path).is_some() {
2208                                         decl_lookup(w, &DeclType::MirroredEnum, &resolved_path, is_ref, is_mut);
2209                                 } else if let Some(t) = self.crate_types.traits.get(&resolved_path) {
2210                                         decl_lookup(w, &DeclType::Trait(t), &resolved_path, is_ref, is_mut);
2211                                 } else if let Some(ident) = single_ident_generic_path_to_ident(&p.path) {
2212                                         if let Some(decl_type) = self.types.maybe_resolve_declared(ident) {
2213                                                 decl_lookup(w, decl_type, &self.maybe_resolve_ident(ident).unwrap(), is_ref, is_mut);
2214                                         } else { unimplemented!(); }
2215                                 } else {
2216                                         if let Some(trait_impls) = self.crate_types.traits_impld.get(&resolved_path) {
2217                                                 if trait_impls.len() == 1 {
2218                                                         // If this is a no-export'd crate and there's only one implementation
2219                                                         // in the whole crate, just treat it as a reference to whatever the
2220                                                         // implementor is.
2221                                                         let implementor = self.crate_types.opaques.get(&trait_impls[0]).unwrap();
2222                                                         decl_lookup(w, &DeclType::StructImported { generics: &implementor.1 }, &trait_impls[0], true, is_mut);
2223                                                         return;
2224                                                 }
2225                                         }
2226                                         unimplemented!();
2227                                 }
2228                         },
2229                         syn::Type::Array(a) => {
2230                                 if let syn::Type::Path(p) = &*a.elem {
2231                                         let inner_ty = self.resolve_path(&p.path, generics);
2232                                         if let syn::Expr::Lit(l) = &a.len {
2233                                                 if let syn::Lit::Int(i) = &l.lit {
2234                                                         write!(w, "{}", path_lookup(&format!("[{}; {}]", inner_ty, i.base10_digits()), is_ref, ptr_for_ref).unwrap()).unwrap();
2235                                                 } else { unimplemented!(); }
2236                                         } else { unimplemented!(); }
2237                                 } else { unimplemented!(); }
2238                         },
2239                         syn::Type::Slice(s) => {
2240                                 // We assume all slices contain only literals or references.
2241                                 // This may result in some outputs not compiling.
2242                                 if let syn::Type::Path(p) = &*s.elem {
2243                                         let resolved = self.resolve_path(&p.path, generics);
2244                                         if self.is_primitive(&resolved) {
2245                                                 write!(w, "{}", path_lookup("[u8]", is_ref, ptr_for_ref).unwrap()).unwrap();
2246                                         } else {
2247                                                 write!(w, "{}", sliceconv(true, None)).unwrap();
2248                                         }
2249                                 } else if let syn::Type::Reference(r) = &*s.elem {
2250                                         if let syn::Type::Path(p) = &*r.elem {
2251                                                 write!(w, "{}", sliceconv(self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)), None)).unwrap();
2252                                         } else if let syn::Type::Slice(_) = &*r.elem {
2253                                                 write!(w, "{}", sliceconv(false, None)).unwrap();
2254                                         } else { unimplemented!(); }
2255                                 } else if let syn::Type::Tuple(t) = &*s.elem {
2256                                         assert!(!t.elems.is_empty());
2257                                         if prefix {
2258                                                 write!(w, "{}", sliceconv(false, None)).unwrap();
2259                                         } else {
2260                                                 let mut needs_map = false;
2261                                                 for e in t.elems.iter() {
2262                                                         if let syn::Type::Reference(_) = e {
2263                                                                 needs_map = true;
2264                                                         }
2265                                                 }
2266                                                 if needs_map {
2267                                                         let mut map_str = Vec::new();
2268                                                         write!(&mut map_str, ".map(|(").unwrap();
2269                                                         for i in 0..t.elems.len() {
2270                                                                 write!(&mut map_str, "{}{}", if i != 0 { ", " } else { "" }, ('a' as u8 + i as u8) as char).unwrap();
2271                                                         }
2272                                                         write!(&mut map_str, ")| (").unwrap();
2273                                                         for (idx, e) in t.elems.iter().enumerate() {
2274                                                                 if let syn::Type::Reference(_) = e {
2275                                                                         write!(&mut map_str, "{}{}", if idx != 0 { ", " } else { "" }, (idx as u8 + 'a' as u8) as char).unwrap();
2276                                                                 } else if let syn::Type::Path(_) = e {
2277                                                                         write!(&mut map_str, "{}*{}", if idx != 0 { ", " } else { "" }, (idx as u8 + 'a' as u8) as char).unwrap();
2278                                                                 } else { unimplemented!(); }
2279                                                         }
2280                                                         write!(&mut map_str, "))").unwrap();
2281                                                         write!(w, "{}", sliceconv(false, Some(&String::from_utf8(map_str).unwrap()))).unwrap();
2282                                                 } else {
2283                                                         write!(w, "{}", sliceconv(false, None)).unwrap();
2284                                                 }
2285                                         }
2286                                 } else if let syn::Type::Array(_) = &*s.elem {
2287                                         write!(w, "{}", sliceconv(false, Some(".map(|a| *a)"))).unwrap();
2288                                 } else { unimplemented!(); }
2289                         },
2290                         syn::Type::Tuple(t) => {
2291                                 if t.elems.is_empty() {
2292                                         // cbindgen has poor support for (), see, eg https://github.com/eqrion/cbindgen/issues/527
2293                                         // so work around it by just pretending its a 0u8
2294                                         write!(w, "{}", tupleconv).unwrap();
2295                                 } else {
2296                                         if prefix { write!(w, "local_").unwrap(); }
2297                                 }
2298                         },
2299                         _ => unimplemented!(),
2300                 }
2301         }
2302
2303         fn write_to_c_conversion_inline_prefix_inner<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, ptr_for_ref: bool, from_ptr: bool) {
2304                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, ptr_for_ref, "() /*", true, |_, _| "local_".to_owned(),
2305                                 |a, b, c| self.to_c_conversion_inline_prefix_from_path(a, b, c),
2306                                 |w, decl_type, decl_path, is_ref, _is_mut| {
2307                                         match decl_type {
2308                                                 DeclType::MirroredEnum if is_ref && ptr_for_ref => write!(w, "crate::{}::from_native(", decl_path).unwrap(),
2309                                                 DeclType::MirroredEnum if is_ref => write!(w, "&crate::{}::from_native(", decl_path).unwrap(),
2310                                                 DeclType::MirroredEnum => write!(w, "crate::{}::native_into(", decl_path).unwrap(),
2311                                                 DeclType::EnumIgnored {..}|DeclType::StructImported {..} if is_ref && from_ptr => {
2312                                                         if !ptr_for_ref { write!(w, "&").unwrap(); }
2313                                                         write!(w, "crate::{} {{ inner: unsafe {{ (", decl_path).unwrap()
2314                                                 },
2315                                                 DeclType::EnumIgnored {..}|DeclType::StructImported {..} if is_ref => {
2316                                                         if !ptr_for_ref { write!(w, "&").unwrap(); }
2317                                                         write!(w, "crate::{} {{ inner: unsafe {{ ObjOps::nonnull_ptr_to_inner((", decl_path).unwrap()
2318                                                 },
2319                                                 DeclType::EnumIgnored {..}|DeclType::StructImported {..} if !is_ref && from_ptr =>
2320                                                         write!(w, "crate::{} {{ inner: ", decl_path).unwrap(),
2321                                                 DeclType::EnumIgnored {..}|DeclType::StructImported {..} if !is_ref =>
2322                                                         write!(w, "crate::{} {{ inner: ObjOps::heap_alloc(", decl_path).unwrap(),
2323                                                 DeclType::Trait(_) if is_ref => write!(w, "").unwrap(),
2324                                                 DeclType::Trait(_) if !is_ref => write!(w, "Into::into(").unwrap(),
2325                                                 _ => panic!("{:?}", decl_path),
2326                                         }
2327                                 });
2328         }
2329         pub fn write_to_c_conversion_inline_prefix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, ptr_for_ref: bool) {
2330                 self.write_to_c_conversion_inline_prefix_inner(w, t, generics, false, ptr_for_ref, false);
2331         }
2332         fn write_to_c_conversion_inline_suffix_inner<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, ptr_for_ref: bool, from_ptr: bool) {
2333                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, ptr_for_ref, "*/", false, |_, _| ".into()".to_owned(),
2334                                 |a, b, c| self.to_c_conversion_inline_suffix_from_path(a, b, c),
2335                                 |w, decl_type, full_path, is_ref, _is_mut| match decl_type {
2336                                         DeclType::MirroredEnum => write!(w, ")").unwrap(),
2337                                         DeclType::EnumIgnored { generics }|DeclType::StructImported { generics } if is_ref => {
2338                                                 write!(w, " as *const {}<", full_path).unwrap();
2339                                                 for param in generics.params.iter() {
2340                                                         if let syn::GenericParam::Lifetime(_) = param {
2341                                                                 write!(w, "'_, ").unwrap();
2342                                                         } else {
2343                                                                 write!(w, "_, ").unwrap();
2344                                                         }
2345                                                 }
2346                                                 if from_ptr {
2347                                                         write!(w, ">) as *mut _ }}, is_owned: false }}").unwrap();
2348                                                 } else {
2349                                                         write!(w, ">) as *mut _) }}, is_owned: false }}").unwrap();
2350                                                 }
2351                                         },
2352                                         DeclType::EnumIgnored {..}|DeclType::StructImported {..} if !is_ref && from_ptr =>
2353                                                 write!(w, ", is_owned: true }}").unwrap(),
2354                                         DeclType::EnumIgnored {..}|DeclType::StructImported {..} if !is_ref => write!(w, "), is_owned: true }}").unwrap(),
2355                                         DeclType::Trait(_) if is_ref => {},
2356                                         DeclType::Trait(_) => {
2357                                                 // This is used when we're converting a concrete Rust type into a C trait
2358                                                 // for use when a Rust trait method returns an associated type.
2359                                                 // Because all of our C traits implement From<RustTypesImplementingTraits>
2360                                                 // we can just call .into() here and be done.
2361                                                 write!(w, ")").unwrap()
2362                                         },
2363                                         _ => unimplemented!(),
2364                                 });
2365         }
2366         pub fn write_to_c_conversion_inline_suffix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, ptr_for_ref: bool) {
2367                 self.write_to_c_conversion_inline_suffix_inner(w, t, generics, false, ptr_for_ref, false);
2368         }
2369
2370         fn write_from_c_conversion_prefix_inner<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, _ptr_for_ref: bool) {
2371                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, false, "() /*", true, |_, _| "&local_".to_owned(),
2372                                 |a, b, _c| self.from_c_conversion_prefix_from_path(a, b),
2373                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
2374                                         DeclType::StructImported {..} if is_ref => write!(w, "").unwrap(),
2375                                         DeclType::StructImported {..} if !is_ref => write!(w, "*unsafe {{ Box::from_raw(").unwrap(),
2376                                         DeclType::MirroredEnum if is_ref => write!(w, "&").unwrap(),
2377                                         DeclType::MirroredEnum => {},
2378                                         DeclType::Trait(_) => {},
2379                                         _ => unimplemented!(),
2380                                 });
2381         }
2382         pub fn write_from_c_conversion_prefix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
2383                 self.write_from_c_conversion_prefix_inner(w, t, generics, false, false);
2384         }
2385         fn write_from_c_conversion_suffix_inner<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, ptr_for_ref: bool) {
2386                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, false, "*/", false,
2387                                 |has_inner, map_str_opt| match (has_inner, map_str_opt) {
2388                                         (false, Some(map_str)) => format!(".iter(){}.collect::<Vec<_>>()[..]", map_str),
2389                                         (false, None) => ".iter().collect::<Vec<_>>()[..]".to_owned(),
2390                                         (true, None) => "[..]".to_owned(),
2391                                         (true, Some(_)) => unreachable!(),
2392                                 },
2393                                 |a, b, _c| self.from_c_conversion_suffix_from_path(a, b),
2394                                 |w, decl_type, _full_path, is_ref, is_mut| match decl_type {
2395                                         DeclType::StructImported {..} if is_ref && ptr_for_ref => write!(w, "XXX unimplemented").unwrap(),
2396                                         DeclType::StructImported {..} if is_mut && is_ref => write!(w, ".get_native_mut_ref()").unwrap(),
2397                                         DeclType::StructImported {..} if is_ref => write!(w, ".get_native_ref()").unwrap(),
2398                                         DeclType::StructImported {..} if !is_ref => write!(w, ".take_inner()) }}").unwrap(),
2399                                         DeclType::MirroredEnum if is_ref => write!(w, ".to_native()").unwrap(),
2400                                         DeclType::MirroredEnum => write!(w, ".into_native()").unwrap(),
2401                                         DeclType::Trait(_) => {},
2402                                         _ => unimplemented!(),
2403                                 });
2404         }
2405         pub fn write_from_c_conversion_suffix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
2406                 self.write_from_c_conversion_suffix_inner(w, t, generics, false, false);
2407         }
2408         // Note that compared to the above conversion functions, the following two are generally
2409         // significantly undertested:
2410         pub fn write_from_c_conversion_to_ref_prefix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
2411                 self.write_conversion_inline_intern(w, t, generics, false, false, false, "() /*", true, |_, _| "&local_".to_owned(),
2412                                 |a, b, _c| {
2413                                         if let Some(conv) = self.from_c_conversion_prefix_from_path(a, b) {
2414                                                 Some(format!("&{}", conv))
2415                                         } else { None }
2416                                 },
2417                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
2418                                         DeclType::StructImported {..} if !is_ref => write!(w, "").unwrap(),
2419                                         _ => unimplemented!(),
2420                                 });
2421         }
2422         pub fn write_from_c_conversion_to_ref_suffix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
2423                 self.write_conversion_inline_intern(w, t, generics, false, false, false, "*/", false,
2424                                 |has_inner, map_str_opt| match (has_inner, map_str_opt) {
2425                                         (false, Some(map_str)) => format!(".iter(){}.collect::<Vec<_>>()[..]", map_str),
2426                                         (false, None) => ".iter().collect::<Vec<_>>()[..]".to_owned(),
2427                                         (true, None) => "[..]".to_owned(),
2428                                         (true, Some(_)) => unreachable!(),
2429                                 },
2430                                 |a, b, _c| self.from_c_conversion_suffix_from_path(a, b),
2431                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
2432                                         DeclType::StructImported {..} if !is_ref => write!(w, ".get_native_ref()").unwrap(),
2433                                         _ => unimplemented!(),
2434                                 });
2435         }
2436
2437         fn write_conversion_new_var_intern<'b, W: std::io::Write,
2438                 LP: Fn(&str, bool) -> Option<(&str, &str)>,
2439                 LC: Fn(&str, bool, Option<&syn::Type>, &syn::Ident, &str) ->  Option<(&'b str, Vec<(String, String)>, &'b str, ContainerPrefixLocation)>,
2440                 VP: Fn(&mut W, &syn::Type, Option<&GenericTypes>, bool, bool, bool),
2441                 VS: Fn(&mut W, &syn::Type, Option<&GenericTypes>, bool, bool, bool)>
2442                         (&self, w: &mut W, ident: &syn::Ident, var: &str, t: &syn::Type, generics: Option<&GenericTypes>,
2443                          mut is_ref: bool, mut ptr_for_ref: bool, to_c: bool, from_ownable_ref: bool,
2444                          path_lookup: &LP, container_lookup: &LC, var_prefix: &VP, var_suffix: &VS) -> bool {
2445
2446                 macro_rules! convert_container {
2447                         ($container_type: expr, $args_len: expr, $args_iter: expr) => { {
2448                                 // For slices (and Options), we refuse to directly map them as is_ref when they
2449                                 // aren't opaque types containing an inner pointer. This is due to the fact that,
2450                                 // in both cases, the actual higher-level type is non-is_ref.
2451                                 let (ty_has_inner, ty_is_trait) = if $args_len == 1 {
2452                                         let ty = $args_iter().next().unwrap();
2453                                         if $container_type == "Slice" && to_c {
2454                                                 // "To C ptr_for_ref" means "return the regular object with is_owned
2455                                                 // set to false", which is totally what we want in a slice if we're about to
2456                                                 // set ty_has_inner.
2457                                                 ptr_for_ref = true;
2458                                         }
2459                                         if let syn::Type::Reference(t) = ty {
2460                                                 if let syn::Type::Path(p) = &*t.elem {
2461                                                         let resolved = self.resolve_path(&p.path, generics);
2462                                                         (self.c_type_has_inner_from_path(&resolved), self.crate_types.traits.get(&resolved).is_some())
2463                                                 } else { (false, false) }
2464                                         } else if let syn::Type::Path(p) = ty {
2465                                                 let resolved = self.resolve_path(&p.path, generics);
2466                                                 (self.c_type_has_inner_from_path(&resolved), self.crate_types.traits.get(&resolved).is_some())
2467                                         } else { (false, false) }
2468                                 } else { (true, false) };
2469
2470                                 // Options get a bunch of special handling, since in general we map Option<>al
2471                                 // types into the same C type as non-Option-wrapped types. This ends up being
2472                                 // pretty manual here and most of the below special-cases are for Options.
2473                                 let mut needs_ref_map = false;
2474                                 let mut only_contained_type = None;
2475                                 let mut only_contained_type_nonref = None;
2476                                 let mut only_contained_has_inner = false;
2477                                 let mut contains_slice = false;
2478                                 if $args_len == 1 {
2479                                         only_contained_has_inner = ty_has_inner;
2480                                         let arg = $args_iter().next().unwrap();
2481                                         if let syn::Type::Reference(t) = arg {
2482                                                 only_contained_type = Some(arg);
2483                                                 only_contained_type_nonref = Some(&*t.elem);
2484                                                 if let syn::Type::Path(_) = &*t.elem {
2485                                                         is_ref = true;
2486                                                 } else if let syn::Type::Slice(_) = &*t.elem {
2487                                                         contains_slice = true;
2488                                                 } else { return false; }
2489                                                 // If the inner element contains an inner pointer, we will just use that,
2490                                                 // avoiding the need to map elements to references. Otherwise we'll need to
2491                                                 // do an extra mapping step.
2492                                                 needs_ref_map = !only_contained_has_inner && !ty_is_trait && $container_type == "Option";
2493                                         } else {
2494                                                 only_contained_type = Some(arg);
2495                                                 only_contained_type_nonref = Some(arg);
2496                                         }
2497                                 }
2498
2499                                 if let Some((prefix, conversions, suffix, prefix_location)) = container_lookup(&$container_type, is_ref, only_contained_type, ident, var) {
2500                                         assert_eq!(conversions.len(), $args_len);
2501                                         write!(w, "let mut local_{}{} = ", ident,
2502                                                 if (!to_c && needs_ref_map) || (to_c && $container_type == "Option" && contains_slice) {"_base"} else { "" }).unwrap();
2503                                         if prefix_location == ContainerPrefixLocation::OutsideConv {
2504                                                 var_prefix(w, $args_iter().next().unwrap(), generics, is_ref, true, true);
2505                                         }
2506                                         write!(w, "{}{}", prefix, var).unwrap();
2507
2508                                         for ((pfx, var_name), (idx, ty)) in conversions.iter().zip($args_iter().enumerate()) {
2509                                                 let mut var = std::io::Cursor::new(Vec::new());
2510                                                 write!(&mut var, "{}", var_name).unwrap();
2511                                                 let var_access = String::from_utf8(var.into_inner()).unwrap();
2512
2513                                                 let conv_ty = if needs_ref_map { only_contained_type_nonref.as_ref().unwrap() } else { ty };
2514
2515                                                 write!(w, "{} {{ ", pfx).unwrap();
2516                                                 let new_var_name = format!("{}_{}", ident, idx);
2517                                                 let new_var = self.write_conversion_new_var_intern(w, &format_ident!("{}", new_var_name),
2518                                                                 &var_access, conv_ty, generics, contains_slice || (is_ref && ty_has_inner), ptr_for_ref,
2519                                                                 to_c, from_ownable_ref, path_lookup, container_lookup, var_prefix, var_suffix);
2520                                                 if new_var { write!(w, " ").unwrap(); }
2521
2522                                                 if prefix_location == ContainerPrefixLocation::PerConv {
2523                                                         var_prefix(w, conv_ty, generics, is_ref && ty_has_inner, ptr_for_ref, false);
2524                                                 } else if !is_ref && !needs_ref_map && to_c && only_contained_has_inner {
2525                                                         write!(w, "ObjOps::heap_alloc(").unwrap();
2526                                                 }
2527
2528                                                 write!(w, "{}{}", if contains_slice && !to_c { "local_" } else { "" }, if new_var { new_var_name } else { var_access }).unwrap();
2529                                                 if prefix_location == ContainerPrefixLocation::PerConv {
2530                                                         var_suffix(w, conv_ty, generics, is_ref && ty_has_inner, ptr_for_ref, false);
2531                                                 } else if !is_ref && !needs_ref_map && to_c && only_contained_has_inner {
2532                                                         write!(w, ")").unwrap();
2533                                                 }
2534                                                 write!(w, " }}").unwrap();
2535                                         }
2536                                         write!(w, "{}", suffix).unwrap();
2537                                         if prefix_location == ContainerPrefixLocation::OutsideConv {
2538                                                 var_suffix(w, $args_iter().next().unwrap(), generics, is_ref, ptr_for_ref, true);
2539                                         }
2540                                         write!(w, ";").unwrap();
2541                                         if !to_c && needs_ref_map {
2542                                                 write!(w, " let mut local_{} = local_{}_base.as_ref()", ident, ident).unwrap();
2543                                                 if contains_slice {
2544                                                         write!(w, ".map(|a| &a[..])").unwrap();
2545                                                 }
2546                                                 write!(w, ";").unwrap();
2547                                         } else if to_c && $container_type == "Option" && contains_slice {
2548                                                 write!(w, " let mut local_{} = *local_{}_base;", ident, ident).unwrap();
2549                                         }
2550                                         return true;
2551                                 }
2552                         } }
2553                 }
2554
2555                 match generics.resolve_type(t) {
2556                         syn::Type::Reference(r) => {
2557                                 if let syn::Type::Slice(_) = &*r.elem {
2558                                         self.write_conversion_new_var_intern(w, ident, var, &*r.elem, generics, is_ref, ptr_for_ref, to_c, from_ownable_ref, path_lookup, container_lookup, var_prefix, var_suffix)
2559                                 } else {
2560                                         self.write_conversion_new_var_intern(w, ident, var, &*r.elem, generics, true, ptr_for_ref, to_c, from_ownable_ref, path_lookup, container_lookup, var_prefix, var_suffix)
2561                                 }
2562                         },
2563                         syn::Type::Path(p) => {
2564                                 if p.qself.is_some() {
2565                                         unimplemented!();
2566                                 }
2567                                 let resolved_path = self.resolve_path(&p.path, generics);
2568                                 if let Some(aliased_type) = self.crate_types.type_aliases.get(&resolved_path) {
2569                                         return self.write_conversion_new_var_intern(w, ident, var, aliased_type, None, is_ref, ptr_for_ref, to_c, from_ownable_ref, path_lookup, container_lookup, var_prefix, var_suffix);
2570                                 }
2571                                 if self.is_known_container(&resolved_path, is_ref) || self.is_path_transparent_container(&p.path, generics, is_ref) {
2572                                         if let syn::PathArguments::AngleBracketed(args) = &p.path.segments.iter().next().unwrap().arguments {
2573                                                 convert_container!(resolved_path, args.args.len(), || args.args.iter().map(|arg| {
2574                                                         if let syn::GenericArgument::Type(ty) = arg {
2575                                                                 generics.resolve_type(ty)
2576                                                         } else { unimplemented!(); }
2577                                                 }));
2578                                         } else { unimplemented!(); }
2579                                 }
2580                                 if self.is_primitive(&resolved_path) {
2581                                         false
2582                                 } else if let Some(ty_ident) = single_ident_generic_path_to_ident(&p.path) {
2583                                         if let Some((prefix, suffix)) = path_lookup(&resolved_path, is_ref) {
2584                                                 write!(w, "let mut local_{} = {}{}{};", ident, prefix, var, suffix).unwrap();
2585                                                 true
2586                                         } else if self.types.maybe_resolve_declared(ty_ident).is_some() {
2587                                                 false
2588                                         } else { false }
2589                                 } else { false }
2590                         },
2591                         syn::Type::Array(_) => {
2592                                 // We assume all arrays contain only primitive types.
2593                                 // This may result in some outputs not compiling.
2594                                 false
2595                         },
2596                         syn::Type::Slice(s) => {
2597                                 if let syn::Type::Path(p) = &*s.elem {
2598                                         let resolved = self.resolve_path(&p.path, generics);
2599                                         if self.is_primitive(&resolved) {
2600                                                 let slice_path = format!("[{}]", resolved);
2601                                                 if let Some((prefix, suffix)) = path_lookup(&slice_path, true) {
2602                                                         write!(w, "let mut local_{} = {}{}{};", ident, prefix, var, suffix).unwrap();
2603                                                         true
2604                                                 } else { false }
2605                                         } else {
2606                                                 let tyref = [&*s.elem];
2607                                                 if to_c {
2608                                                         // If we're converting from a slice to a Vec, assume we can clone the
2609                                                         // elements and clone them into a new Vec first. Next we'll walk the
2610                                                         // new Vec here and convert them to C types.
2611                                                         write!(w, "let mut local_{}_clone = Vec::new(); local_{}_clone.extend_from_slice({}); let mut {} = local_{}_clone; ", ident, ident, ident, ident, ident).unwrap();
2612                                                 }
2613                                                 is_ref = false;
2614                                                 convert_container!("Vec", 1, || tyref.iter().map(|t| generics.resolve_type(*t)));
2615                                                 unimplemented!("convert_container should return true as container_lookup should succeed for slices");
2616                                         }
2617                                 } else if let syn::Type::Reference(ty) = &*s.elem {
2618                                         let tyref = if from_ownable_ref || !to_c { [&*ty.elem] } else { [&*s.elem] };
2619                                         is_ref = true;
2620                                         convert_container!("Slice", 1, || tyref.iter().map(|t| generics.resolve_type(*t)));
2621                                         unimplemented!("convert_container should return true as container_lookup should succeed for slices");
2622                                 } else if let syn::Type::Tuple(t) = &*s.elem {
2623                                         // When mapping into a temporary new var, we need to own all the underlying objects.
2624                                         // Thus, we drop any references inside the tuple and convert with non-reference types.
2625                                         let mut elems = syn::punctuated::Punctuated::new();
2626                                         for elem in t.elems.iter() {
2627                                                 if let syn::Type::Reference(r) = elem {
2628                                                         elems.push((*r.elem).clone());
2629                                                 } else {
2630                                                         elems.push(elem.clone());
2631                                                 }
2632                                         }
2633                                         let ty = [syn::Type::Tuple(syn::TypeTuple {
2634                                                 paren_token: t.paren_token, elems
2635                                         })];
2636                                         is_ref = false;
2637                                         ptr_for_ref = true;
2638                                         convert_container!("Slice", 1, || ty.iter());
2639                                         unimplemented!("convert_container should return true as container_lookup should succeed for slices");
2640                                 } else if let syn::Type::Array(_) = &*s.elem {
2641                                         is_ref = false;
2642                                         ptr_for_ref = true;
2643                                         let arr_elem = [(*s.elem).clone()];
2644                                         convert_container!("Slice", 1, || arr_elem.iter());
2645                                         unimplemented!("convert_container should return true as container_lookup should succeed for slices");
2646                                 } else { unimplemented!() }
2647                         },
2648                         syn::Type::Tuple(t) => {
2649                                 if !t.elems.is_empty() {
2650                                         // We don't (yet) support tuple elements which cannot be converted inline
2651                                         write!(w, "let (").unwrap();
2652                                         for idx in 0..t.elems.len() {
2653                                                 if idx != 0 { write!(w, ", ").unwrap(); }
2654                                                 write!(w, "{} orig_{}_{}", if is_ref { "ref" } else { "mut" }, ident, idx).unwrap();
2655                                         }
2656                                         write!(w, ") = {}{}; ", var, if !to_c { ".to_rust()" } else { "" }).unwrap();
2657                                         // Like other template types, tuples are always mapped as their non-ref
2658                                         // versions for types which have different ref mappings. Thus, we convert to
2659                                         // non-ref versions and handle opaque types with inner pointers manually.
2660                                         for (idx, elem) in t.elems.iter().enumerate() {
2661                                                 if let syn::Type::Path(p) = elem {
2662                                                         let v_name = format!("orig_{}_{}", ident, idx);
2663                                                         let tuple_elem_ident = format_ident!("{}", &v_name);
2664                                                         if self.write_conversion_new_var_intern(w, &tuple_elem_ident, &v_name, elem, generics,
2665                                                                         false, ptr_for_ref, to_c, from_ownable_ref,
2666                                                                         path_lookup, container_lookup, var_prefix, var_suffix) {
2667                                                                 write!(w, " ").unwrap();
2668                                                                 // Opaque types with inner pointers shouldn't ever create new stack
2669                                                                 // variables, so we don't handle it and just assert that it doesn't
2670                                                                 // here.
2671                                                                 assert!(!self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)));
2672                                                         }
2673                                                 }
2674                                         }
2675                                         write!(w, "let mut local_{} = (", ident).unwrap();
2676                                         for (idx, elem) in t.elems.iter().enumerate() {
2677                                                 let real_elem = generics.resolve_type(&elem);
2678                                                 let ty_has_inner = {
2679                                                                 if to_c {
2680                                                                         // "To C ptr_for_ref" means "return the regular object with
2681                                                                         // is_owned set to false", which is totally what we want
2682                                                                         // if we're about to set ty_has_inner.
2683                                                                         ptr_for_ref = true;
2684                                                                 }
2685                                                                 if let syn::Type::Reference(t) = real_elem {
2686                                                                         if let syn::Type::Path(p) = &*t.elem {
2687                                                                                 self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
2688                                                                         } else { false }
2689                                                                 } else if let syn::Type::Path(p) = real_elem {
2690                                                                         self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
2691                                                                 } else { false }
2692                                                         };
2693                                                 if idx != 0 { write!(w, ", ").unwrap(); }
2694                                                 var_prefix(w, real_elem, generics, is_ref && ty_has_inner, ptr_for_ref, false);
2695                                                 if is_ref && ty_has_inner {
2696                                                         // For ty_has_inner, the regular var_prefix mapping will take a
2697                                                         // reference, so deref once here to make sure we keep the original ref.
2698                                                         write!(w, "*").unwrap();
2699                                                 }
2700                                                 write!(w, "orig_{}_{}", ident, idx).unwrap();
2701                                                 if is_ref && !ty_has_inner {
2702                                                         // If we don't have an inner variable's reference to maintain, just
2703                                                         // hope the type is Clonable and use that.
2704                                                         write!(w, ".clone()").unwrap();
2705                                                 }
2706                                                 var_suffix(w, real_elem, generics, is_ref && ty_has_inner, ptr_for_ref, false);
2707                                         }
2708                                         write!(w, "){};", if to_c { ".into()" } else { "" }).unwrap();
2709                                         true
2710                                 } else { false }
2711                         },
2712                         _ => unimplemented!(),
2713                 }
2714         }
2715
2716         pub fn write_to_c_conversion_new_var_inner<W: std::io::Write>(&self, w: &mut W, ident: &syn::Ident, var_access: &str, t: &syn::Type, generics: Option<&GenericTypes>, ptr_for_ref: bool, from_ownable_ref: bool) -> bool {
2717                 self.write_conversion_new_var_intern(w, ident, var_access, t, generics, from_ownable_ref, ptr_for_ref, true, from_ownable_ref,
2718                         &|a, b| self.to_c_conversion_new_var_from_path(a, b),
2719                         &|a, b, c, d, e| self.to_c_conversion_container_new_var(generics, a, b, c, d, e),
2720                         // We force ptr_for_ref here since we can't generate a ref on one line and use it later
2721                         &|a, b, c, d, e, f| self.write_to_c_conversion_inline_prefix_inner(a, b, c, d, e, f),
2722                         &|a, b, c, d, e, f| self.write_to_c_conversion_inline_suffix_inner(a, b, c, d, e, f))
2723         }
2724         pub fn write_to_c_conversion_new_var<W: std::io::Write>(&self, w: &mut W, ident: &syn::Ident, t: &syn::Type, generics: Option<&GenericTypes>, ptr_for_ref: bool) -> bool {
2725                 self.write_to_c_conversion_new_var_inner(w, ident, &format!("{}", ident), t, generics, ptr_for_ref, false)
2726         }
2727         /// Prints new-var conversion for an "ownable_ref" type, ie prints conversion for
2728         /// `create_ownable_reference(t)`, not `t` itself.
2729         pub fn write_to_c_conversion_from_ownable_ref_new_var<W: std::io::Write>(&self, w: &mut W, ident: &syn::Ident, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
2730                 self.write_to_c_conversion_new_var_inner(w, ident, &format!("{}", ident), t, generics, true, true)
2731         }
2732         pub fn write_from_c_conversion_new_var<W: std::io::Write>(&self, w: &mut W, ident: &syn::Ident, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
2733                 self.write_conversion_new_var_intern(w, ident, &format!("{}", ident), t, generics, false, false, false, false,
2734                         &|a, b| self.from_c_conversion_new_var_from_path(a, b),
2735                         &|a, b, c, d, e| self.from_c_conversion_container_new_var(generics, a, b, c, d, e),
2736                         // We force ptr_for_ref here since we can't generate a ref on one line and use it later
2737                         &|a, b, c, d, e, _f| self.write_from_c_conversion_prefix_inner(a, b, c, d, e),
2738                         &|a, b, c, d, e, _f| self.write_from_c_conversion_suffix_inner(a, b, c, d, e))
2739         }
2740
2741         // ******************************************************
2742         // *** C Container Type Equivalent and alias Printing ***
2743         // ******************************************************
2744
2745         fn write_template_generics<'b, W: std::io::Write>(&self, w: &mut W, args: &mut dyn Iterator<Item=&'b syn::Type>, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
2746                 for (idx, orig_t) in args.enumerate() {
2747                         if idx != 0 {
2748                                 write!(w, ", ").unwrap();
2749                         }
2750                         let t = generics.resolve_type(orig_t);
2751                         if let syn::Type::Reference(r_arg) = t {
2752                                 assert!(!is_ref); // We don't currently support outer reference types for non-primitive inners
2753
2754                                 if !self.write_c_type_intern(w, &*r_arg.elem, generics, false, false, false, true, true) { return false; }
2755
2756                                 // While write_c_type_intern, above is correct, we don't want to blindly convert a
2757                                 // reference to something stupid, so check that the container is either opaque or a
2758                                 // predefined type (currently only Transaction).
2759                                 if let syn::Type::Path(p_arg) = &*r_arg.elem {
2760                                         let resolved = self.resolve_path(&p_arg.path, generics);
2761                                         assert!(self.crate_types.opaques.get(&resolved).is_some() ||
2762                                                         self.crate_types.traits.get(&resolved).is_some() ||
2763                                                         self.c_type_from_path(&resolved, true, true).is_some(), "Template generics should be opaque or have a predefined mapping");
2764                                 } else { unimplemented!(); }
2765                         } else if let syn::Type::Path(p_arg) = t {
2766                                 if let Some(resolved) = self.maybe_resolve_path(&p_arg.path, generics) {
2767                                         if !self.is_primitive(&resolved) && self.c_type_from_path(&resolved, false, false).is_none() {
2768                                                 if is_ref {
2769                                                         // We don't currently support outer reference types for non-primitive inners
2770                                                         return false;
2771                                                 }
2772                                         }
2773                                 } else {
2774                                         return false;
2775                                 }
2776                                 if !self.write_c_type_intern(w, t, generics, false, false, false, true, true) { return false; }
2777                         } else {
2778                                 // We don't currently support outer reference types for non-primitive inners,
2779                                 // except for the empty tuple.
2780                                 if let syn::Type::Tuple(t_arg) = t {
2781                                         assert!(t_arg.elems.len() == 0 || !is_ref);
2782                                 } else {
2783                                         assert!(!is_ref);
2784                                 }
2785                                 if !self.write_c_type_intern(w, t, generics, false, false, false, true, true) { return false; }
2786                         }
2787                 }
2788                 true
2789         }
2790         fn check_create_container(&self, mangled_container: String, container_type: &str, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
2791                 if !self.crate_types.templates_defined.borrow().get(&mangled_container).is_some() {
2792                         let mut created_container: Vec<u8> = Vec::new();
2793
2794                         if container_type == "Result" {
2795                                 let mut a_ty: Vec<u8> = Vec::new();
2796                                 if let syn::Type::Tuple(tup) = args.iter().next().unwrap() {
2797                                         if tup.elems.is_empty() {
2798                                                 write!(&mut a_ty, "()").unwrap();
2799                                         } else {
2800                                                 if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t).take(1), generics, is_ref) { return false; }
2801                                         }
2802                                 } else {
2803                                         if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t).take(1), generics, is_ref) { return false; }
2804                                 }
2805
2806                                 let mut b_ty: Vec<u8> = Vec::new();
2807                                 if let syn::Type::Tuple(tup) = args.iter().skip(1).next().unwrap() {
2808                                         if tup.elems.is_empty() {
2809                                                 write!(&mut b_ty, "()").unwrap();
2810                                         } else {
2811                                                 if !self.write_template_generics(&mut b_ty, &mut args.iter().map(|t| *t).skip(1), generics, is_ref) { return false; }
2812                                         }
2813                                 } else {
2814                                         if !self.write_template_generics(&mut b_ty, &mut args.iter().map(|t| *t).skip(1), generics, is_ref) { return false; }
2815                                 }
2816
2817                                 let ok_str = String::from_utf8(a_ty).unwrap();
2818                                 let err_str = String::from_utf8(b_ty).unwrap();
2819                                 let is_clonable = self.is_clonable(&ok_str) && self.is_clonable(&err_str);
2820                                 write_result_block(&mut created_container, &mangled_container, &ok_str, &err_str, is_clonable);
2821                                 if is_clonable {
2822                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2823                                 }
2824                         } else if container_type == "Vec" {
2825                                 let mut a_ty: Vec<u8> = Vec::new();
2826                                 if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t), generics, is_ref) { return false; }
2827                                 let ty = String::from_utf8(a_ty).unwrap();
2828                                 let is_clonable = self.is_clonable(&ty);
2829                                 write_vec_block(&mut created_container, &mangled_container, &ty, is_clonable);
2830                                 if is_clonable {
2831                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2832                                 }
2833                         } else if container_type.ends_with("Tuple") {
2834                                 let mut tuple_args = Vec::new();
2835                                 let mut is_clonable = true;
2836                                 for arg in args.iter() {
2837                                         let mut ty: Vec<u8> = Vec::new();
2838                                         if !self.write_template_generics(&mut ty, &mut [arg].iter().map(|t| **t), generics, is_ref) { return false; }
2839                                         let ty_str = String::from_utf8(ty).unwrap();
2840                                         if !self.is_clonable(&ty_str) {
2841                                                 is_clonable = false;
2842                                         }
2843                                         tuple_args.push(ty_str);
2844                                 }
2845                                 write_tuple_block(&mut created_container, &mangled_container, &tuple_args, is_clonable);
2846                                 if is_clonable {
2847                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2848                                 }
2849                         } else if container_type == "Option" {
2850                                 let mut a_ty: Vec<u8> = Vec::new();
2851                                 if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t), generics, is_ref) { return false; }
2852                                 let ty = String::from_utf8(a_ty).unwrap();
2853                                 let is_clonable = self.is_clonable(&ty);
2854                                 write_option_block(&mut created_container, &mangled_container, &ty, is_clonable);
2855                                 if is_clonable {
2856                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2857                                 }
2858                         } else {
2859                                 unreachable!();
2860                         }
2861                         self.crate_types.write_new_template(mangled_container.clone(), true, &created_container);
2862                 }
2863                 true
2864         }
2865         fn path_to_generic_args(path: &syn::Path) -> Vec<&syn::Type> {
2866                 if let syn::PathArguments::AngleBracketed(args) = &path.segments.iter().next().unwrap().arguments {
2867                         args.args.iter().map(|gen| if let syn::GenericArgument::Type(t) = gen { t } else { unimplemented!() }).collect()
2868                 } else { unimplemented!(); }
2869         }
2870         fn write_c_mangled_container_path_intern<W: std::io::Write>
2871                         (&self, w: &mut W, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, ident: &str, is_ref: bool, is_mut: bool, ptr_for_ref: bool, in_type: bool) -> bool {
2872                 let mut mangled_type: Vec<u8> = Vec::new();
2873                 if !self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a), generics) {
2874                         write!(w, "C{}_", ident).unwrap();
2875                         write!(mangled_type, "C{}_", ident).unwrap();
2876                 } else { assert_eq!(args.len(), 1); }
2877                 for arg in args.iter() {
2878                         macro_rules! write_path {
2879                                 ($p_arg: expr, $extra_write: expr) => {
2880                                         if let Some(subtype) = self.maybe_resolve_path(&$p_arg.path, generics) {
2881                                                 if self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a), generics) {
2882                                                         if !in_type {
2883                                                                 if self.c_type_has_inner_from_path(&subtype) {
2884                                                                         if !self.write_c_path_intern(w, &$p_arg.path, generics, is_ref, is_mut, ptr_for_ref, false, true) { return false; }
2885                                                                 } else {
2886                                                                         // Option<T> needs to be converted to a *mut T, ie mut ptr-for-ref
2887                                                                         if !self.write_c_path_intern(w, &$p_arg.path, generics, true, true, true, false, true) { return false; }
2888                                                                 }
2889                                                         } else {
2890                                                                 write!(w, "{}", $p_arg.path.segments.last().unwrap().ident).unwrap();
2891                                                         }
2892                                                 } else if self.is_known_container(&subtype, is_ref) || self.is_path_transparent_container(&$p_arg.path, generics, is_ref) {
2893                                                         if !self.write_c_mangled_container_path_intern(w, Self::path_to_generic_args(&$p_arg.path), generics,
2894                                                                         &subtype, is_ref, is_mut, ptr_for_ref, true) {
2895                                                                 return false;
2896                                                         }
2897                                                         self.write_c_mangled_container_path_intern(&mut mangled_type, Self::path_to_generic_args(&$p_arg.path),
2898                                                                 generics, &subtype, is_ref, is_mut, ptr_for_ref, true);
2899                                                         if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
2900                                                                 self.write_c_mangled_container_path_intern(w2, Self::path_to_generic_args(&$p_arg.path),
2901                                                                         generics, &subtype, is_ref, is_mut, ptr_for_ref, true);
2902                                                         }
2903                                                 } else {
2904                                                         let mut resolved = Vec::new();
2905                                                         let id =
2906                                                                 if self.write_c_path_intern(&mut resolved, &$p_arg.path, generics, false, false, false, false, false) {
2907                                                                         let inner = std::str::from_utf8(&resolved).unwrap();
2908                                                                         inner.rsplitn(2, "::").next().unwrap()
2909                                                                 } else {
2910                                                                         subtype.rsplitn(2, "::").next().unwrap()
2911                                                                 };
2912                                                         write!(w, "{}", id).unwrap();
2913                                                         write!(mangled_type, "{}", id).unwrap();
2914                                                         if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
2915                                                                 write!(w2, "{}", id).unwrap();
2916                                                         }
2917                                                 }
2918                                         } else { return false; }
2919                                 }
2920                         }
2921                         match generics.resolve_type(arg) {
2922                                 syn::Type::Tuple(tuple) => {
2923                                         if tuple.elems.len() == 0 {
2924                                                 write!(w, "None").unwrap();
2925                                                 write!(mangled_type, "None").unwrap();
2926                                         } else {
2927                                                 let mut mangled_tuple_type: Vec<u8> = Vec::new();
2928
2929                                                 // Figure out what the mangled type should look like. To disambiguate
2930                                                 // ((A, B), C) and (A, B, C) we prefix the generic args with a _ and suffix
2931                                                 // them with a Z. Ideally we wouldn't use Z, but not many special chars are
2932                                                 // available for use in type names.
2933                                                 write!(w, "C{}Tuple_", tuple.elems.len()).unwrap();
2934                                                 write!(mangled_type, "C{}Tuple_", tuple.elems.len()).unwrap();
2935                                                 write!(mangled_tuple_type, "C{}Tuple_", tuple.elems.len()).unwrap();
2936                                                 for elem in tuple.elems.iter() {
2937                                                         if let syn::Type::Path(p) = elem {
2938                                                                 write_path!(p, Some(&mut mangled_tuple_type));
2939                                                         } else if let syn::Type::Reference(refelem) = elem {
2940                                                                 if let syn::Type::Path(p) = &*refelem.elem {
2941                                                                         write_path!(p, Some(&mut mangled_tuple_type));
2942                                                                 } else { return false; }
2943                                                         } else if let syn::Type::Array(_) = elem {
2944                                                                 let mut resolved = Vec::new();
2945                                                                 if !self.write_c_type_intern(&mut resolved, &elem, generics, false, false, false, false, false) { return false; }
2946                                                                 let array_inner = String::from_utf8(resolved).unwrap();
2947                                                                 let arr_name = array_inner.rsplitn(2, "::").next().unwrap();
2948                                                                 write!(w, "{}", arr_name).unwrap();
2949                                                                 write!(mangled_type, "{}", arr_name).unwrap();
2950                                                         } else { return false; }
2951                                                 }
2952                                                 write!(w, "Z").unwrap();
2953                                                 write!(mangled_type, "Z").unwrap();
2954                                                 write!(mangled_tuple_type, "Z").unwrap();
2955                                                 if !self.check_create_container(String::from_utf8(mangled_tuple_type).unwrap(),
2956                                                                 &format!("{}Tuple", tuple.elems.len()), tuple.elems.iter().collect(), generics, is_ref) {
2957                                                         return false;
2958                                                 }
2959                                         }
2960                                 },
2961                                 syn::Type::Path(p_arg) => {
2962                                         write_path!(p_arg, None);
2963                                 },
2964                                 syn::Type::Reference(refty) => {
2965                                         if let syn::Type::Path(p_arg) = &*refty.elem {
2966                                                 write_path!(p_arg, None);
2967                                         } else if let syn::Type::Slice(_) = &*refty.elem {
2968                                                 // write_c_type will actually do exactly what we want here, we just need to
2969                                                 // make it a pointer so that its an option. Note that we cannot always convert
2970                                                 // the Vec-as-slice (ie non-ref types) containers, so sometimes need to be able
2971                                                 // to edit it, hence we use *mut here instead of *const.
2972                                                 if args.len() != 1 { return false; }
2973                                                 write!(w, "*mut ").unwrap();
2974                                                 self.write_c_type(w, arg, None, true);
2975                                         } else { return false; }
2976                                 },
2977                                 syn::Type::Array(a) => {
2978                                         if let syn::Type::Path(p_arg) = &*a.elem {
2979                                                 let resolved = self.resolve_path(&p_arg.path, generics);
2980                                                 if !self.is_primitive(&resolved) { return false; }
2981                                                 if let syn::Expr::Lit(syn::ExprLit { lit: syn::Lit::Int(len), .. }) = &a.len {
2982                                                         if self.c_type_from_path(&format!("[{}; {}]", resolved, len.base10_digits()), is_ref, ptr_for_ref).is_none() { return false; }
2983                                                         if in_type || args.len() != 1 {
2984                                                                 write!(w, "_{}{}", resolved, len.base10_digits()).unwrap();
2985                                                                 write!(mangled_type, "_{}{}", resolved, len.base10_digits()).unwrap();
2986                                                         } else {
2987                                                                 let arrty = format!("[{}; {}]", resolved, len.base10_digits());
2988                                                                 let realty = self.c_type_from_path(&arrty, is_ref, ptr_for_ref).unwrap_or(&arrty);
2989                                                                 write!(w, "{}", realty).unwrap();
2990                                                                 write!(mangled_type, "{}", realty).unwrap();
2991                                                         }
2992                                                 } else { return false; }
2993                                         } else { return false; }
2994                                 },
2995                                 _ => { return false; },
2996                         }
2997                 }
2998                 if self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a), generics) { return true; }
2999                 // Push the "end of type" Z
3000                 write!(w, "Z").unwrap();
3001                 write!(mangled_type, "Z").unwrap();
3002
3003                 // Make sure the type is actually defined:
3004                 self.check_create_container(String::from_utf8(mangled_type).unwrap(), ident, args, generics, is_ref)
3005         }
3006         fn write_c_mangled_container_path<W: std::io::Write>(&self, w: &mut W, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, ident: &str, is_ref: bool, is_mut: bool, ptr_for_ref: bool) -> bool {
3007                 if !self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a), generics) {
3008                         write!(w, "{}::", Self::generated_container_path()).unwrap();
3009                 }
3010                 self.write_c_mangled_container_path_intern(w, args, generics, ident, is_ref, is_mut, ptr_for_ref, false)
3011         }
3012         pub fn get_c_mangled_container_type(&self, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, template_name: &str) -> Option<String> {
3013                 let mut out = Vec::new();
3014                 if !self.write_c_mangled_container_path(&mut out, args, generics, template_name, false, false, false) {
3015                         return None;
3016                 }
3017                 Some(String::from_utf8(out).unwrap())
3018         }
3019
3020         // **********************************
3021         // *** C Type Equivalent Printing ***
3022         // **********************************
3023
3024         fn write_c_path_intern<W: std::io::Write>(&self, w: &mut W, path: &syn::Path, generics: Option<&GenericTypes>, is_ref: bool, is_mut: bool, ptr_for_ref: bool, with_ref_lifetime: bool, c_ty: bool) -> bool {
3025                 let full_path = match self.maybe_resolve_path(&path, generics) {
3026                         Some(path) => path, None => return false };
3027                 if let Some(c_type) = self.c_type_from_path(&full_path, is_ref, ptr_for_ref) {
3028                         write!(w, "{}", c_type).unwrap();
3029                         true
3030                 } else if self.crate_types.traits.get(&full_path).is_some() {
3031                         // Note that we always use the crate:: prefix here as we are always referring to a
3032                         // concrete object which is of the generated type, it just implements the upstream
3033                         // type.
3034                         if is_ref && ptr_for_ref {
3035                                 write!(w, "*{} crate::{}", if is_mut { "mut" } else { "const" }, full_path).unwrap();
3036                         } else if is_ref {
3037                                 if with_ref_lifetime { unimplemented!(); }
3038                                 write!(w, "&{}crate::{}", if is_mut { "mut " } else { "" }, full_path).unwrap();
3039                         } else {
3040                                 write!(w, "crate::{}", full_path).unwrap();
3041                         }
3042                         true
3043                 } else if self.crate_types.opaques.get(&full_path).is_some() || self.crate_types.mirrored_enums.get(&full_path).is_some() {
3044                         let crate_pfx = if c_ty { "crate::" } else { "" };
3045                         if is_ref && ptr_for_ref {
3046                                 // ptr_for_ref implies we're returning the object, which we can't really do for
3047                                 // opaque or mirrored types without box'ing them, which is quite a waste, so return
3048                                 // the actual object itself (for opaque types we'll set the pointer to the actual
3049                                 // type and note that its a reference).
3050                                 write!(w, "{}{}", crate_pfx, full_path).unwrap();
3051                         } else if is_ref && with_ref_lifetime {
3052                                 assert!(!is_mut);
3053                                 // If we're concretizing something with a lifetime parameter, we have to pick a
3054                                 // lifetime, of which the only real available choice is `static`, obviously.
3055                                 write!(w, "&'static {}", crate_pfx).unwrap();
3056                                 if !c_ty {
3057                                         self.write_rust_path(w, generics, path, with_ref_lifetime, false);
3058                                 } else {
3059                                         // We shouldn't be mapping references in types, so panic here
3060                                         unimplemented!();
3061                                 }
3062                         } else if is_ref {
3063                                 write!(w, "&{}{}{}", if is_mut { "mut " } else { "" }, crate_pfx, full_path).unwrap();
3064                         } else {
3065                                 write!(w, "{}{}", crate_pfx, full_path).unwrap();
3066                         }
3067                         true
3068                 } else {
3069                         if let Some(trait_impls) = self.crate_types.traits_impld.get(&full_path) {
3070                                 if trait_impls.len() == 1 {
3071                                         // If this is a no-export'd crate and there's only one implementation in the
3072                                         // whole crate, just treat it as a reference to whatever the implementor is.
3073                                         if with_ref_lifetime {
3074                                                 // Hope we're being printed in function generics and let rustc derive the
3075                                                 // type.
3076                                                 write!(w, "_").unwrap();
3077                                         } else {
3078                                                 write!(w, "&crate::{}", trait_impls[0]).unwrap();
3079                                         }
3080                                         return true;
3081                                 }
3082                         }
3083                         false
3084                 }
3085         }
3086         fn write_c_type_intern<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, is_mut: bool, ptr_for_ref: bool, with_ref_lifetime: bool, c_ty: bool) -> bool {
3087                 match generics.resolve_type(t) {
3088                         syn::Type::Path(p) => {
3089                                 if p.qself.is_some() {
3090                                         return false;
3091                                 }
3092                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
3093                                         if self.is_known_container(&full_path, is_ref) || self.is_path_transparent_container(&p.path, generics, is_ref) {
3094                                                 return self.write_c_mangled_container_path(w, Self::path_to_generic_args(&p.path), generics, &full_path, is_ref, is_mut, ptr_for_ref);
3095                                         }
3096                                         if let Some(aliased_type) = self.crate_types.type_aliases.get(&full_path).cloned() {
3097                                                 return self.write_c_type_intern(w, &aliased_type, None, is_ref, is_mut, ptr_for_ref, with_ref_lifetime, c_ty);
3098                                         }
3099                                 }
3100                                 self.write_c_path_intern(w, &p.path, generics, is_ref, is_mut, ptr_for_ref, with_ref_lifetime, c_ty)
3101                         },
3102                         syn::Type::Reference(r) => {
3103                                 self.write_c_type_intern(w, &*r.elem, generics, true, r.mutability.is_some(), ptr_for_ref, with_ref_lifetime, c_ty)
3104                         },
3105                         syn::Type::Array(a) => {
3106                                 if is_ref && is_mut {
3107                                         write!(w, "*mut [").unwrap();
3108                                         if !self.write_c_type_intern(w, &a.elem, generics, false, false, ptr_for_ref, with_ref_lifetime, c_ty) { return false; }
3109                                 } else if is_ref {
3110                                         write!(w, "*const [").unwrap();
3111                                         if !self.write_c_type_intern(w, &a.elem, generics, false, false, ptr_for_ref, with_ref_lifetime, c_ty) { return false; }
3112                                 }
3113                                 if let syn::Expr::Lit(l) = &a.len {
3114                                         if let syn::Lit::Int(i) = &l.lit {
3115                                                 let mut inner_ty = Vec::new();
3116                                                 if !self.write_c_type_intern(&mut inner_ty, &*a.elem, generics, false, false, ptr_for_ref, false, c_ty) { return false; }
3117                                                 let inner_ty_str = String::from_utf8(inner_ty).unwrap();
3118                                                 if !is_ref {
3119                                                         if let Some(ty) = self.c_type_from_path(&format!("[{}; {}]", inner_ty_str, i.base10_digits()), false, ptr_for_ref) {
3120                                                                 write!(w, "{}", ty).unwrap();
3121                                                                 true
3122                                                         } else { false }
3123                                                 } else {
3124                                                         write!(w, "; {}]", i).unwrap();
3125                                                         true
3126                                                 }
3127                                         } else { false }
3128                                 } else { false }
3129                         }
3130                         syn::Type::Slice(s) => {
3131                                 if !is_ref || is_mut { return false; }
3132                                 if let syn::Type::Path(p) = &*s.elem {
3133                                         let resolved = self.resolve_path(&p.path, generics);
3134                                         if self.is_primitive(&resolved) {
3135                                                 write!(w, "{}::{}slice", Self::container_templ_path(), resolved).unwrap();
3136                                                 true
3137                                         } else {
3138                                                 let mut inner_c_ty = Vec::new();
3139                                                 assert!(self.write_c_path_intern(&mut inner_c_ty, &p.path, generics, true, false, ptr_for_ref, with_ref_lifetime, c_ty));
3140                                                 let inner_ty_str = String::from_utf8(inner_c_ty).unwrap();
3141                                                 if self.is_clonable(&inner_ty_str) {
3142                                                         let inner_ty_ident = inner_ty_str.rsplitn(2, "::").next().unwrap();
3143                                                         let mangled_container = format!("CVec_{}Z", inner_ty_ident);
3144                                                         write!(w, "{}::{}", Self::generated_container_path(), mangled_container).unwrap();
3145                                                         self.check_create_container(mangled_container, "Vec", vec![&*s.elem], generics, false)
3146                                                 } else { false }
3147                                         }
3148                                 } else if let syn::Type::Reference(r) = &*s.elem {
3149                                         if let syn::Type::Path(p) = &*r.elem {
3150                                                 // Slices with "real types" inside are mapped as the equivalent non-ref Vec
3151                                                 let resolved = self.resolve_path(&p.path, generics);
3152                                                 let mangled_container = if let Some((ident, _)) = self.crate_types.opaques.get(&resolved) {
3153                                                         format!("CVec_{}Z", ident)
3154                                                 } else if let Some(en) = self.crate_types.mirrored_enums.get(&resolved) {
3155                                                         format!("CVec_{}Z", en.ident)
3156                                                 } else if let Some(id) = p.path.get_ident() {
3157                                                         format!("CVec_{}Z", id)
3158                                                 } else { return false; };
3159                                                 write!(w, "{}::{}", Self::generated_container_path(), mangled_container).unwrap();
3160                                                 self.check_create_container(mangled_container, "Vec", vec![&*r.elem], generics, false)
3161                                         } else if let syn::Type::Slice(sl2) = &*r.elem {
3162                                                 if let syn::Type::Reference(r2) = &*sl2.elem {
3163                                                         if let syn::Type::Path(p) = &*r2.elem {
3164                                                                 // Slices with slices with opaque types (with is_owned flags) are mapped as non-ref Vecs
3165                                                                 let resolved = self.resolve_path(&p.path, generics);
3166                                                                 let mangled_container = if let Some((ident, _)) = self.crate_types.opaques.get(&resolved) {
3167                                                                         format!("CVec_CVec_{}ZZ", ident)
3168                                                                 } else { return false; };
3169                                                                 write!(w, "{}::{}", Self::generated_container_path(), mangled_container).unwrap();
3170                                                                 let inner = &r2.elem;
3171                                                                 let vec_ty: syn::Type = syn::parse_quote!(Vec<#inner>);
3172                                                                 self.check_create_container(mangled_container, "Vec", vec![&vec_ty], generics, false)
3173                                                         } else { false }
3174                                                 } else { false }
3175                                         } else { false }
3176                                 } else if let syn::Type::Tuple(_) = &*s.elem {
3177                                         let mut args = syn::punctuated::Punctuated::<_, syn::token::Comma>::new();
3178                                         args.push(syn::GenericArgument::Type((*s.elem).clone()));
3179                                         let mut segments = syn::punctuated::Punctuated::new();
3180                                         segments.push(parse_quote!(Vec<#args>));
3181                                         self.write_c_type_intern(w, &syn::Type::Path(syn::TypePath { qself: None, path: syn::Path { leading_colon: None, segments } }), generics, false, is_mut, ptr_for_ref, with_ref_lifetime, c_ty)
3182                                 } else if let syn::Type::Array(a) = &*s.elem {
3183                                         if let syn::Expr::Lit(l) = &a.len {
3184                                                 if let syn::Lit::Int(i) = &l.lit {
3185                                                         let mut buf = Vec::new();
3186                                                         self.write_rust_type(&mut buf, generics, &*a.elem, false);
3187                                                         let arr_ty = String::from_utf8(buf).unwrap();
3188
3189                                                         let arr_str = format!("[{}; {}]", arr_ty, i.base10_digits());
3190                                                         let ty = self.c_type_from_path(&arr_str, false, ptr_for_ref).unwrap()
3191                                                                 .rsplitn(2, "::").next().unwrap();
3192
3193                                                         let mangled_container = format!("CVec_{}Z", ty);
3194                                                         write!(w, "{}::{}", Self::generated_container_path(), mangled_container).unwrap();
3195                                                         self.check_create_container(mangled_container, "Vec", vec![&*s.elem], generics, false)
3196                                                 } else { false }
3197                                         } else { false }
3198                                 } else { false }
3199                         },
3200                         syn::Type::Tuple(t) => {
3201                                 if t.elems.len() == 0 {
3202                                         true
3203                                 } else {
3204                                         self.write_c_mangled_container_path(w, t.elems.iter().collect(), generics,
3205                                                 &format!("{}Tuple", t.elems.len()), is_ref, is_mut, ptr_for_ref)
3206                                 }
3207                         },
3208                         _ => false,
3209                 }
3210         }
3211         pub fn write_c_type<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, ptr_for_ref: bool) {
3212                 assert!(self.write_c_type_intern(w, t, generics, false, false, ptr_for_ref, false, true));
3213         }
3214         pub fn write_c_type_in_generic_param<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, ptr_for_ref: bool) {
3215                 assert!(self.write_c_type_intern(w, t, generics, false, false, ptr_for_ref, true, false));
3216         }
3217         pub fn understood_c_path(&self, p: &syn::Path) -> bool {
3218                 self.write_c_path_intern(&mut std::io::sink(), p, None, false, false, false, false, true)
3219         }
3220         pub fn understood_c_type(&self, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
3221                 self.write_c_type_intern(&mut std::io::sink(), t, generics, false, false, false, false, true)
3222         }
3223 }